Basics of Chemistry and

Latest DevelopmentsBy Dr. Roman Saini

Basics of Chemistry

Matter and its States

● The matter is defined as anything that has mass and volume i.e. it occupies space and is made up of particles.

● The four fundamental states of matter are:

a. Solid, b. Liquid, c. Gas and d. Plasma.

● Bose-Einstein condensate is sometimes considered the fifth state of matter.● The fermionic condensate which is a cloud of cold potassium atoms forced

into a state where they behave strangely is considered as the sixth state of matter.

1. The solid state

● Solids have a definite shape and volume and do not take up the shape of the container in which they are placed.

● The particles that make up solids are placed close to each other and have low kinetic energy.

● The electrons of each atom are in motion, so the atoms have a small vibration, but they are fixed in their position.

Types of Solid1. Crystalline solids- ● In crystalline solids, the atoms, ions or molecules are arranged in an

ordered and symmetrical pattern that is repeated over the entire crystal.

● Because there are repeated units, crystals have recognizable structures.● The smallest repeating structure of a solid is called a unit cell and unit cells

together form a network called crystal lattice. ● The scientific study of crystals is called Crystallography. ● Examples of crystals:

○ Gemstones – diamond, sapphire, quartz etc.○ Sugar, Table salt, Snowflakes etc.

2. Amorphous solids-

● In amorphous solids, the particles do not have any characteristic symmetry due to lack of a repeating lattice pattern.

● They are also called "pseudo solids."

● Examples include glass, rubber, talcum powder, and most plastics.

2. The Liquid State

● The particles of a liquid do not have a regular arrangement and have more kinetic energy than solid particles.

● The particles are very close to each other, the intermolecular space is more than that of solids and less than that of gases, so liquids have a definite volume.

● Particles of a liquid can flow around each other so liquids have an indefinite shape.

● A liquid takes up the shape of the container.

● Examples- Water, solutions, alcohol etc.

3.The Gaseous State

● Gas particles have much more space between them when compared to solids and liquids.

● The gas particles spread out in space and fill up the container if they are contained in one. This property of gas is called diffusion.

● Gas particles have enough kinetic energy to overcome intermolecular forces that hold solids and liquids together.

● Thus, a gas has no definite volume and no definite shape.

4. The Plasma

• Plasma is the fourth fundamental state of matter.

• Plasma comprises a hot ionized gas consisting of approximately equal numbers of positively charged ions and negatively charged electrons.

• Like gas, plasma does not have a definite shape or a definite volume unless enclosed in a container;

• Unlike gas, under the influence of a magnetic field, it may form structures such as filaments, beams and double layers.

● Plasma exists in a great amount in the universe.

● It is said that 99.9% of the universe is plasma.

● Some common plasma is found in stars and neon signs.

● Examples of plasma- solar corona, solar winds releasing from the sun's corona.

● Plasma can be found in many instruments of everyday use like Plasma TV, Neon Lights etc.

5. Bose-Einstein Condensate● They are sometimes considered the fifth state of matter.● They were artificially created in the laboratory in 1995.● However, their existence was predicted by Albert Einstein and Satyendra

Nath Bose in 1924-25. ● To create BEC, the magnetic fields and lasers are employed to cool atoms to

an extremely low temperature — just above minus 273.15 C, or absolute zero.

● The motion of the atoms almost stops at the extremely low temperature. ● Since there is almost no kinetic energy being transferred from one atom to

another, the atoms begin to clump together.

● There are no longer thousands of separate atoms, just one “super atom.”

● BEC state is extremely fragile and the slightest increase in temperature or interaction with external environment converts the state to normal gas state.

● Eric Cornell, Carl Wieman, and co-workers created BEC using rubidium atoms.

● They won the 2001 Nobel Prize in Physics for it.

● BEC was created for the first time in India at TIFR in 2007.

6.Fermionic Condensate

● A fermionic condensate is a superfluid phase formed by fermionic particles at low temperatures.

● It is closely related to the Bose-Einstein condensate, a superfluid phase formed by bosonic atoms under similar conditions.

● Like the Bose-Einstein condensates, Fermi condensates will coalesce (grow together into one entity).

● Both are man-made states of matter.

● The particles that make these states of matter have to be artificially super-cooled, to have the properties that they do.

● However, Fermi condensates have reached even lower temperatures than Bose-Einstein condensates.

● Also, both states of matter have no viscosity, which means that they can flow without stopping.

Phase Transition

● In simple words, phase transition means that due to a change in conditions like temperature or pressure, the phase of matter changes to another phase.

● Some examples are

○ Melting- Solid to Liquid

○ Freezing- Liquid to Solid

○ Vaporization- Liquid to gas

○ Condensation- Gas to Liquid

Phase Transition- Melting

● At a standard pressure, when heat is applied to a solid, its temperature increases, its particles begin to vibrate faster and tend to move farther apart.

● After a certain point when the temperature is high enough, the solid melts and turns into a liquid.

● The process of melting, that is, change of solid state into the liquid state is also known as fusion.

● Melting point- It is the temperature for a solid at which it changes from solid to a liquid state at atmospheric pressure.

Phase Transition- Freezing

● When the liquid state turns into solid the state, the process is called freezing.

● Freezing point- The temperature at which the liquid changes into solid.

Phase Transition- Evaporation

● In this process, liquid state is converted to the gaseous state.

● Two forms of vaporization are boiling and evaporation.

● When the liquid gets enough heat and bubbles of vapor from below the surface of the liquid, the process is called boiling.

● In evaporation, a small fraction of particles of liquid at the surface, have higher kinetic energy and are able to break away from the forces of attraction of other particles.

● They get converted into vapour.

● Evaporation occurs at any temperature below the boiling point of the liquid.

● It is commonly found in many natural processes.

● It is an important part of the water cycle.

Factors affecting the rate of evaporation:● Surface area: If the surface area is increased, the rate of evaporation

increases.● Temperature: With the increase of temperature, evaporation increases as

more number of particles get enough kinetic energy to go into the vapour state.

● Humidity: Humidity is the amount of water vapour present in the air. When an amount of water in the air is already high, the rate of evaporation decreases.

● Wind speed: With the increase in wind speed, the particles of water vapour move away with the wind, decreasing the amount of water vapour in the surrounding, thus the rate of evaporation increases.

Examples of evaporation-

● Clothes drying- while drying clothes, the clothes are spread. This increases the surface area and thus, the rate of evaporation.

● Also, when the temperature is high, humidity is less, and it’s windy the clothes dry faster.

● Cooling of the body through sweat.

● Water cooling in the earthen pitcher.

● Natural salt deposits

Phase Transition- Condensation

●The cooling down of vapours and turning into the liquid state.

●E.g. water vapour condensing to water droplets.

Phase Transition- Sublimation

● When a solid is converted directly into a gas without going through a liquid phase, the process is known as sublimation.

● Sublimation occurs when the kinetic energy of the particles is greater than atmospheric pressure surrounding the sample.

● E.g. dry ice or solid carbon dioxide.

Phase Transition- Deposition, Ionization and Recombination

Deposition-

● Gas turns into solid without going through the solid state.

Ionization-

● Gaseous state turns into plasma when the gas atoms lose or gain electrons and therefore the gas becomes either positively or negatively charged.

Recombination-

● This is the reversal of ionization state when plasma turns into gas.

Substances

What is a substance?● In chemistry, a substance is anything that has a definite chemical

composition.

● Substances are pure or impure.

Pure substances-

● They have a uniform composition.

● Pure elements and compounds are examples of it.

○ Elements- The pure form of gold, silver or other metals.

○ Compounds- Pure water which will be composed of two hydrogen atoms and one oxygen atom whether collected from rain or river.

Impure substances-

● Mixtures are common impure substances.

○ Homogeneous mixture- The composition is uniform throughout. Examples- Sugar solution in water, salt solution in water.

○ Heterogeneous mixture- the composition is not uniform. Examples- blood, the mixture of oil and water where two separate layers can be seen.

Pure Substances- Elements & Compounds

Pure Substances- Elements● An element is a chemical substance that usually cannot be broken down

into any simpler substances by chemical reactions. (exceptions-certain radioactive elements)

● An element is formed from only one type of atom.● Elements can exist as either only atoms or join together to form

molecules.● Elements are arranged in the periodic table.● Elements have distinct chemical symbols. E.g. Nitrogen- N, Iron- Fe,

Lead- Pb, Oxygen- O, Chlorine- Cl.● Examples – Helium consists of only one atom; Oxygen is composed of two

atoms (O2); the same is the case with nitrogen (N2).

Molecules● A molecule is formed when two or more atoms bond chemically and are

held tightly by attractive forces.

● The bonding atoms may be of same or different elements.

● Molecules are capable of independent existence and show the physical and chemical properties of the substance.

● Molecules form the smallest unbreakable unit of a compound.

● Atomicity- The number of atoms constituting a molecule.

● Molecular Mass- The molecular mass of a substance is the sum of the atomic masses of all the atoms in a molecule of the substance.

Ions

● An ion is a charged atom or molecule, which can be either positively or negatively charged.

Anion-

● If the atom has more electrons than protons, it is a negative ion called anion.

Cation-

● If the atom has more protons than electrons, it is a positive ion called cation.

● Example- Sodium chloride (NaCl) has constituent particles as positively charged sodium ions (Na+) and negatively charged chloride ions (Cl–).

Allotropes● Some chemical elements exist in two or more different forms due to the

different arrangement of atoms. These forms are known as allotropes of that element.

● Carbon exists in diamond, graphite, fullerenes etc.

● Oxygen has two allotropes viz. Oxygen and Ozone.

● Allotropy is for elements and not for compounds.

● For example, water and ice are not allotropes.

● The changes in state between solid, gas and liquid are not allotropy.

Pure Substances- Compounds● Compounds are formed when atoms of two or more elements join

together by chemical bonds.

● Example- H2O or water is made of hydrogen and oxygen. NaCl or table salt is made of sodium and chlorine atom.

● Compounds can be broken down into the elements that form them. However, this cannot be achieved by physical means.

● Chemical methods are used to break down the compounds into the respective elements forming them.

● Example- Breaking water (H2O) into H-atoms and O-atoms is achieved through a chemical method electrolysis.

● In compounds, the atoms of elements are found in a definite ratio and this ratio stays the same throughout.

● In H2O, the ratio of H-atom to O-atom remains 2:1 throughout, whether the water is found in tap or in the sea on Earth, the water will always be made of H- atoms and O-atom in the ratio of 2:1.

● Compounds may have physical or chemical properties different from the respective elements that form them.

● Compounds are represented using chemical formulae.● For example-

1. NaCl- Table salt2. C6H12O6- Glucose

Ionic Compounds

● Ionic Compounds consist of ions held together by chemical bonds called ionic bonds.

● Ionic compounds contain a metal bonded with a non-metal.

● Some examples of ionic compounds are:

1. Sodium Chloride (NaCl)

2. Magnesium oxide (MgO)

3. Sodium bromide (NaBr)

General Properties of ionic compounds:

● Most of them are crystalline solids.

● They have high melting and boiling points.

● They can conduct electricity when melted.

● Many of ionic compounds are soluble in water or polar solvent but have poor solubility or are insoluble in organic solvents like alcohol.

Covalent Compounds● These compounds consist of atoms held together by chemical bonds

called covalent bonds.● The covalent bond is formed by sharing of electrons.● Most of these compounds have non-metals bonded with each other.● Examples :

a. Ethyl alcohol (CH3CH2OH )b. Hydrogen chloride (HCl)c. Methane (CH4)d. Biomolecules- carbohydrates, proteins, lipids etc.

General Properties of covalent compounds:

● They can be gases, liquids, or solids.

● They have low melting and boiling points.

● They are poor electrical conductors in all phases.

● Many are soluble in non-polar liquids or organic solvents but have poor solubility in polar solvents like water.

Impure Substances- Mixture

● Mixtures consist of two or more different substances.

● It may be elements and/or compounds which are mixed mechanically but not combined chemically.

● Mixtures are formed from at least two different types of atoms, or at least two different types of molecules, or at least one type of atom and at least one type of molecule.

● Unlike compounds which have a specific ratio of the respective atoms, mixtures do not have a specific ratio of the constituents forming them.

Mixture

● Unlike compounds, mixtures can be separated into their constituents by physical means.

● Mixtures have many of the properties of their constituents.

● Example, air is a mixture of many gases. Air exists in the gaseous form, same as nitrogen, hydrogen or oxygen forming it.

● Elements and compounds have specific melting and boiling points whereas mixtures show phase transitions across a range of temperatures.

Type of Mixture- Solution

Solutions:

● A solution is a homogeneous mixture made of solute and a solvent.

Solvent:

● The component of the solution that dissolves the other component in it and is usually present in the larger amount than solute.

Solute:

● The other component of the solution that is dissolved in the solvent and is usually present in lesser quantity than the solvent.

Solubility-

● It is a general term used for the ability of a solute to dissolve in a liquid solvent.

● Generally, it is used for a solid solute dissolving in a liquid solvent.

Miscibility-

● The ability of a liquid to dissolve in another liquid.

● It is a more specific term.

Miscible Liquids:

● Miscible liquids are the liquids that mix together and form a solution.

● Example- solution of water and alcohol.

Immiscible Liquids:

● Immiscible liquids do not mix with each other and form a suspension rather than a homogenous solution.

● The two liquids can be seen in two layers, with the heavier one sinking to the bottom of the container.

● E.g. a mixture of oil and water in which the oil droplets float over water.

Properties of Solution:

● Solution particles do not scatter a beam of light passing through the solution.

● Solute cannot be separated from the solution through a filtration process, which is a physical method of separation.

● The solution is stable, i.e. when the solution is left undisturbed, the solute particles do not settle down.

Saturated Solution● When the solvent is capable of dissolving at the maximum quantity of

solute to form a solution at any particular temperature, the solution is said to be saturated.

● This means that when a solution is saturated, no more solute can be dissolved and the extra solute can be found at the bottom of the solute.

● A supersaturated solution contains the quantity of solute which is more than that could be dissolved in the solvent under normal conditions

● Therefore, a supersaturated solution contains more solute at a given temperature than is needed to form a saturated solution.

Type of Mixture- Suspension● It is a heterogeneous fluid mixture that contains solid particles large

enough for sedimentation.

● The particles, unlike solutes, in a solution will eventually settle to the bottom of the container.

● Example- particles of sand in water; Medicinal suspension- Gelusil liquid

● The particles of a suspension can be seen by the naked eye and scatter a beam of light passing through it.

● When the suspension is left undisturbed, the particles settle down. Thus, a suspension is unstable.

Types of Mixture- Colloids● It is a heterogeneous mixture that contains particles which are too small

to be visible to the naked eyes.

● However, unlike solutes of a solution, they are big enough to scatter a beam of light passing through it and make its path visible.

● The colloid particles do not settle down when left undisturbed.

● Thus, a colloid is a stable mixture.

● Colloid particles cannot be separated through filtration.

● However, by the method of centrifugation, the particles can be separated.

Types of Mixture- Alloys

● They are mixtures of two or more metals or a metal and a non-metal.

● They cannot be separated into their components by physical methods.

● An alloy is considered as a mixture because it shows the properties of its constituents and can have variable composition.

Alloy Constituents Applications

Bell Metal Copper and Tin Making bells and related musical instruments like cymbals.

Steel Iron and carbonOther elements- Manganese, Chromium, Vanadium, and Tungsten

Cookware;Serveware equipment

Examples of Alloy

Alloy Constituents Applications

Monel Copper and Iron Kitchen-sinks; Frames for eyeglasses

Duralumin Aluminum, Copper, Nickel, Manganese,Magnesium

Aircraft construction; Manufacturing of boats; Railroad cars; Machinery.

Lead-tin solder

Lead and tin, with tin concentrations ranging from 5-70%

Permanent bond between the metal pieces.

Bronze Copper with upto 12% tin Coins and medals; Heavy gears; Tools; Electrical hardware

Methods of Separation

1. Filtration-

● The solid particles in a liquid or gaseous fluid are removed by the use of a porous filter that permits the fluid to pass through but captures the solid particles.

● The liquid or the fluid passing through the filter is called filtrate whereas the substance left behind in the filter is called residue.

● Example- Water filtration system;

● Separating sand from a mixture of water and sand.

2. Evaporation-

● This is a process used to separate solids from liquids.

● Example- separating salt from brine solution.

3. Distillation-

● Used for the separation of components of a mixture containing two miscible liquids that boil without decomposition and have sufficient difference in their boiling points.

4. Fractional distillation-

● Separating a liquid from a mixture of two or more liquids.

● Fractional distillation is used to separate the constituents present in the crude oil.

5. Chromatography-

● Separating dissolved substances that dissolve in the same solvent like inks, food colourings and plant dyes.

● The principle behind it is that some solutes dissolve better in a solvent than other solutes and therefore travel farther on a chromatographic paper.

6. Centrifugation-

● Centrifugal force is used to separate components.

● The principle is that the denser particles are forced to the bottom and the lighter particles stay at the top when spun rapidly.

● Examples- centrifugation is used to separate blood plasma from other; constituents of blood during diagnostic procedures.

Physical and Chemical Changes

Physical Change Chemical Change

It is a change in the physical properties of a substance.

It is the change in the chemical properties of the substance

It usually is reversible. It usually is irreversible.

No new substance is formed. A new substance is formed.

Chemical properties remain the same. Chemical properties will change.

Examples- Melting of ice to form water, Water solidifying to become ice,Forming a solution of salt and water and later evaporating the solution so that salt is left behind.

Examples- Burning of paperRusting of ironBoiling of EggBurning of woodSouring of milkFermentation, Formation of curd etc.

Acids and Bases

Acids Bases

● Acids are chemical compounds that are sour in taste.

● Bases are the chemicals that are bitter in taste and feel soapy on touching.

● They turn blue litmus red. ● They turn red litmus blue.

● An Arrhenius acid increases the concentration of H+ ions or protons in aqueous solution i.e. acids dissociate into protons when they react with water.

● An Arrhenius base increases the concentration of hydroxide ions, OH− ions in aqueous solution i.e. bases dissociate into hydroxide ions when they react with water.

● Hydrochloric acid dissociates into H+ ions and Cl ions in water.

● Sodium hydroxide dissociates in water.

pH Scale

● pH scale is a logarithmic scale that measures acidity and alkalinity.

● The pH scale has a range from 0 to 14.

pH value <7 pH value 7.0 pH value > 7

Indicates Acidity Indicates Neutrality Indicates Alkalinity

pH Indicators● Indicators are substances that show whether the other substance is acidic,

basic or neutral in nature.

● Litmus is a natural indicator extracted from lichens.

● When added to an acidic solution, it turns red and when added to a basic solution, it turns blue.

● Other indicators are Thymol blue, Methyl orange, Methyl red, Phenol red, Phenolphthalein etc.

● A universal indicator is a mixture of indicators which give a gradual change in color over a wide pH range.

Chemical Reactions and Equations

Chemical Reaction

● Chemical Reaction takes place when a chemical change occurs.

● Following signs indicate that a chemical reaction has taken place:

○ Change in state

○ Change in colour

○ Change in temperature

○ Evolution of gas

Chemical Equation● It represents the chemical reaction.

● It involves substance(s) called reactant(s) that undergo the chemical change to form new substance(s) called product(s).

● Example- Magnesium + Oxygen = Magnesium oxide

● A shorter way of writing an equation is using chemical formulae of elements or compounds as

2Mg + O2 2MgO

Oxidation-Reduction Reactions:

● Oxidation- Gain of oxygen by a substance during the chemical reaction.

● Reduction- Loss of oxygen from a substance during a chemical reaction.

● REDOX Reaction- During a chemical reaction when oxidation and reduction take place simultaneously.

● E.g. when Hydrogen Gas reacts with Copper Oxide, the oxide undergoes reduction and loses oxygen atom.

● This oxygen atom is gained by hydrogen to form water (oxidation).

CuO + H2 Cu + H2O

Oxidation in Daily Life● Items of daily use undergo oxidation which usually changes their appearance

or taste or smell in case of food.● Example, when an apple is cut, it soon turns brown, this is due to oxidation.● When a metal is exposed to moisture in the air or acids, it corrodes. ● Examples are rusting of iron and black coating on silver.● Rancidity- Oxidation of oils and fats causes rancidity. Smell and taste of

rancid oils change. ● Adding antioxidants and keeping food in airtight containers help slow

down oxidation. ● Nitrogen gas in chips packets also prevents oxidation of chips.

Metals and Non-metals

Physical Properties of Metals● Most metals, in their pure state, have a shining surface. This property is

called metallic luster.

● Metals are generally hard, with hardness varying from metal to metal.

● All metals except mercury exist as solids at room temperature.

● Some metals show malleability – the property of being beaten into thin sheets.

● Gold and silver are the most malleable metals.

● Ductility- The ability of metals to be drawn into thin wires is called ductility.

● Gold is the most ductile metal.

● Most metals are good conductors of heat.

● The best conductors of heat are silver and copper. Lead and mercury are comparatively poor conductors of heat.

● Most metals are good conductor of electricity. Silver and copper are considered best conductors of electricity.

● Sonorous metals- The metals that produce a sound on striking a hard surface.

● Metals have high melting points but gallium and cesium have very low melting points.

● Most metals have high density. Iridium has the highest density whereas lithium has the lowest density.

Physical Properties of Non-metals● Most of the non-metals have no metallic luster.

● They can exist in all three states of matter at room temperature, but most of them are gases (oxygen, nitrogen, noble gases) or solids (carbon, phosphorus, sulphur).

● Bromine is the only non-metal that exists as the liquid at room temperature.

● Non-metals are very brittle, thus they are not malleable or ductile.

● They are poor conductors of heat and electricity.

Chemical Process- Combustion

● A chemical process in which a substance reacts with oxygen to give off heat is called combustion.

● The substance that undergoes combustion is said to be combustible.

● It is also called a fuel. The fuel may be solid, liquid or gas.

● Sometimes, light is also given off during combustion, either as a flame or as a glow.

● Ignition temperature: The lowest temperature at which a substance catches fire is called its ignition temperature.

● A combustible substance cannot catch fire or burn as long as its temperature is lower than its ignition temperature.

● Kerosene oil and wood do not catch fire on their own at room temperature.

● But, if kerosene oil is heated a little, it will catch fire whereas wood is heated a little, it would still not catch fire.

● It means that the ignition temperature of kerosene oil is lower than that of wood.

● The substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances.

● E.g. petrol, alcohol, Liquified Petroleum Gas (LPG) etc.

● There are three essential requirements for producing fire. These are fuel, air (to supply oxygen) and heat (to raise the temperature of the fuel beyond the ignition temperature).

● Fire can be controlled by removing one or more of these requirements.

Controlling of Fire:● When a fire brigade arrives and it pours water on the fire:

○ Water cools the combustible material so that its temperature is brought below its ignition temperature. This prevents the fire from spreading.

○ Water vapours also surround the combustible material, helping in cutting off the supply of air. So, the fire is extinguished.

● The job of a fire extinguisher is to cut off the supply of the air or to bring down the temperature of the fuel, or both.

● Water works only when things like wood and paper are on fire. ● If electrical equipment is on fire, water may conduct electricity and harm

those trying to douse the fire.

● Water is also not suitable for fires involving oil and petrol. As water is heavier than oil it sinks below the oil, and oil keeps burning on the top.

● For fires involving electrical equipment and inflammable materials like petrol, carbon dioxide (CO2) is the best extinguisher.

● CO2, being heavier than oxygen, covers the fire like a blanket and also brings down the temperature of the fuel. It is an excellent fire extinguisher.

● The added advantage of CO2 is that in most cases it does not harm the electrical equipment.

● Another way to get CO2 is to release a lot of dry powder of chemicals like sodium bicarbonate (baking soda) or potassium bicarbonate.

● Near the fire, these chemicals give off CO2.

Flame

● The substances which vaporize during burning, give flames.

● For example, kerosene oil and molten wax rise through the wick and are vaporized during burning and form flames.

● Charcoal, on the other hand, does not vapourize and so does not produce a flame.

Three zones of a flame:

1. Outer Zone: blue in colour, hottest part of the flame because complete combustion takes place in this zone.

2. Middle Zone: yellow and orange in colour; moderately hot because partial combustion takes place in this zone.

3. Inner Zone: dark in colour; coolest part of the flame because no combustion takes place in this zone.

Electrochemical Cell

● Galvanic or voltaic process- Chemical reactions that result in the production of electrical energy.

● Electrode- Rod-like metal conductors that remain dipped in the electrolytic solution.

● Anode: Electrode in an electrochemical cell on which the oxidation reaction occurs.

● Cathode: Electrode in an electrochemical cell on which the reduction reaction occurs.

● Electromotive force, EMF (or cell potential): Difference of potential energy of electrons between the two electrodes.

● Half-cell reaction- At each electrode, an electrochemical reaction occurs. This reaction is called a half-cell reaction, as there are two electrodes- cathode and anode in a typical cell.

● The two half-cell reactions are combined to form the complete electrochemical reaction.

● Electrolytic processes: Reactions in which chemical changes occur on the passage of an electrical current.

● Electrolysis: The decomposition of a substance by means of electric current.

● Electrolyte: The compound that in aqueous solution or in a fused form (molten form) conducts electricity is called an electrolyte. It also undergoes decomposition when electricity is passed.

● The typical example of an electrochemical cell is the cell containing zinc as anode and copper as a cathode.

● Zinc plate is kept inside the zinc sulphate solution, whereas copper plate is kept in the copper sulphate solution.

● Zinc is more electropositive than copper and loses electrons more readily. ● Thus, oxidation takes place at Zinc electrode which is the anode. Copper

does not lose electrons.● Zinc and copper solutions are connected by electrical wire. ● Once Zn starts losing electrons, the free electrons travel from zinc solution

to copper sulphate solution.● Copper gains electrons and copper get deposited on the plate. Thus, copper

plate represents the cathode where reduction takes place.

Latest Developments

1. The Food

The Food We Eat● Food chemistry studies the chemical processing and production of food.

● Food chemistry includes interactions between the biological components of food.

● The macronutrients – carbohydrates, proteins, and fats.

● The micronutrients- minerals and vitamins are chemical substances.

● Respiration is an important biochemical process that occurs in all living beings.

● Respiration is the conversion of glucose to chemical energy that acts as a fuel for the body.

Cooking

● Cooking methods involve chemical changes that change the appearance, texture, and taste of the food.

● Knowledge about these changes and the chemicals behind them is used in improving the food quality.

● For e.g. baking soda- sodium bicarbonate and baking powder- Sodium hydrogen carbonate are used as leavening agents.

● They cause fermentation in the batter and help the batter to rise while baking.

Artificial Sweeteners● These are sugar substitutes that are sweet but have much less calorific

value than sugar.

● This is why they are advertised as a healthy alternative to sugar and meant for diet conscious and diabetics.

● Common artificial sweeteners:

Saccharin- ● The first artificial sweetener that was the synthesis in the lab. ● It is 300 to 500 times as sweet as sugar. ● It is found to improve the taste of beverages, toothpaste, foods etc.

Stevia- ● It is a natural sweetener and has been used in South America for ages.

● It is a zero calorie sweetener and growing in popularity.

● It is naturally found in the Stevia plant.

Aspartame-● It is about 200 times as sweet as sugar.

● It is used in frozen desserts, chewing gums etc.

● It has been approved fit for human consumption.

● Aspartame is not used in baking because at higher temperatures it breaks down into constituent amino acids.

Sucralose-

● It is chlorinated sugar prepared from two types of sugars- sucrose and raffinose.

● It is almost 600 times sweeter than sugar.

Acesulfame potassium-

● It is almost 200 times sweeter than sugar and is blended with other sweeteners.

● It is commonly used in pharmaceutical preparations, protein shakes etc.

Mogrosides-

● Some mogrosides are naturally found in some plants.

Food Preservatives● Food Preservation is basically done for preserving the natural

characteristics of food and its appearance and for increasing the shelf value of food for storage.

● Natural and artificial food preservatives are used for this purpose.

● They delay the growth of bacteria, spoilage, and discoloration of food.

● Examples of natural preservatives- salt, sugar, alcohol, vinegar.

● Examples of Chemical preservatives-

○ Benzoates like sodium benzoate and benzoic acid

○ Nitrites like sodium nitrite

○ Sulphites

○ Sorbates like sodium sorbate, potassium sorbate

● Antioxidants like Vitamin E, Vitamin C and Butylated hydroxytoluene (BHT) are also used.

● Antioxidants stop the oxidation process that spoils the food.

● Addition of antioxidants prevents the rancidity in oils and fats.

Health Concern related to Food Preservatives:

● Some chemical preservatives are associated with causing health problems.

● Some examples are:

1. Benzoates- allergies, asthma and skin rash and brain damage.

2. Butylated- high blood pressure and cholesterol level, can also affect the kidney and liver function

3. BHA (butylated hydroxyanisole) - liver diseases and cancer. This food preservative is used to preserve the fresh pork and pork sausages, potato chips, instant teas, cake mixes and many more.

4. Caramel- vitamin B6 deficiencies, genetic effects and cancer.

Harmful chemicals found in food substances● Processed foods are generally considered not so well for health.

● The processing of food employs chemical processes and use of certain chemicals that are known to cause health problems, ranging from minor to severe.

● These chemicals include food additives, flavouring substances, texture enhancing substances, food preservatives, artificial sweeteners etc.

● Food contact materials (FCMs) is the term used for compounds used in packaging, storage, processing or preparation processed foods.

● Artificial Blue, Green, Red, And Yellow food colorings are linked to thyroid, adrenal, bladder, kidney, and brain cancers.

● Palm oil- extracted from the fruit of the oil palm tree, this oil has high levels of saturated fats, which can be a significant threat to cardiovascular health.

● Trans-fats present in junk food raises the bad LDL cholesterol and triglycerides and lower the good HDL and increases the risk of blood clots and heart attack

● Sodium Benzoate and Potassium Benzoate are derived from benzene which is a carcinogen.

● Monosodium glutamate (MSG)- a popular food taste and flavour enhancer have the potential to cause brain damage.

● Brominated vegetable oil is used in soft drinks. BVO has been linked to memory loss and problems in brain and nerve function.

2. The Health

pH in Everyday LifepH for Species:

● The body of plants and animals is pH sensitive.

● Our body works within the pH range of 7.0 to 7.8.

● Living organisms can survive only in a narrow range of pH change.

● Plants require a specific pH range for their healthy growth.

● When pH of rainwater is less than 5.6, it is called acid rain.

● When acid rain flows into the rivers, it lowers the pH of the river water.

● The survival of aquatic life in such rivers becomes difficult.

Digestive System:

● Our stomach produces hydrochloric acid that helps in the digestion of food without harming the stomach.

● During indigestion, the stomach produces too much acid and this causes pain and irritation.

● To get rid of this pain, people use bases called antacids. These antacids neutralize the excess acid.

● Magnesium hydroxide (Milk of magnesia), a mild base, is often used for this purpose.

Tooth Decay:

● Tooth decay starts when the pH of the mouth is lower than 5.5.

● Tooth enamel, made up of calcium phosphate is the hardest substance in the body.

● It does not dissolve in water but is corroded when the pH in the mouth is below 5.5.

● Bacteria present in the mouth produce acids by degradation of sugar and food particles remaining in the mouth after eating.

● The best way to prevent this is to clean the mouth after eating food.

● Using toothpaste, which is generally basic, for cleaning the teeth can neutralize the excess acid and prevent tooth decay.

Self defence by animals and plants:

● Bee-sting leaves an acid which causes pain and irritation.

● Use of a mild base like baking soda on the stung area gives relief.

● Stinging hair of nettle leaves injects methanoic acid causing burning pain.

Neutralisation in nature:

● Nettle, a wild plant, has leaves with stinging hair, which cause painful stings when touched accidentally. This is due to the methanoic acid secreted by them.

● A traditional remedy is rubbing the area with the leaf of the dock plant, which often grows beside the nettle in the wild.

Commonly Used Medicinal DrugsAntibiotics-

● They kill microorganisms that cause diseases in the body.

● Antibiotics are most effective against bacterial and fungal infections.

● Notable antibiotics are streptomycin, azithromycin, erythromycin, ciprofloxacin etc.

Analgesics-

● They are painkillers.

● E.g. paracetamol, opioids (morphine).

Antihistamines-

● Used to treat allergies and inflammation.

● Examples- diphenhydramine (Benadryl), cetirizine.

Antacids-

● They are used to treat acid refluxes.

● Bases like calcium carbonate, magnesium hydroxide are used to treat acidity.

● Common drug brands in the market are Gelusil and Digene.

● Nuclear medicine is the use of radioactive substances for diagnosis and cure of diseases.

● The radiopharmaceutical is a radioactive substance that is injected or swallowed by the patient.

● This substance helps in detection of blockages, tumours or any other abnormality in the body.

Nuclear Medicine

3. The Energy

Fuel Cell

● A fuel cell is a kind of electrochemical cell that converts chemical energy in a fuel to electricity.

● The electrochemical reaction takes place between hydrogen fuel with oxygen or oxidizing agent.

● It is mainly used in power generation - portable power generation, stationary power generation, and power for transportation.

● Nuclear reactors use radioactive elements, especially Uranium for generation of electricity.

● The process of nuclear fission is employed here.

● Enrichment of Uranium ore is an often heard topic in news.

● Uranium hexafluoride contains two types of uranium, U-238, and U-235.

● U-235 fissions easily but is present in an amount less than 1 percent.

● To use uranium as a fuel, its U-235 content needs to be increased to between 3 percent and 5 percent. This process is called enrichment.

Nuclear Energy as Fuel

Fossil Fuels● Coal, Petroleum (crude oil and petroleum products) and natural gas

come under fossil fuels.

● Fossil fuels are non-renewable resources that formed when prehistoric plants and marine animals died and were gradually buried by layers of rock.

● Fossil fuels are formed over millions of years and their formation and type depend on the type of organic matter buried, duration of burial, and temperature and pressure conditions.

● Chemically, fossil fuels contain a large amount of carbon.

Formation of fossil fuels:

● Millions of years ago, the remains of plants and animals decayed and deposited in thick layers, and sometimes mixed with sand, silt and rock.

● Deposition of these layers of organic material and mixing with sand, silt, and rock combined with pressure and heat changed the material into fossil fuels.

● In some places, the natural gas moved into large cracks and spaces between layers of overlying rock.

● Coal is largely derived from plant whereas crude oil from marine animals, especially diatoms.

Natural Gas● Natural gas occurs deep beneath the earth's surface.

● It contains chiefly methane, which is a hydrocarbon made up of one carbon atom and four hydrogen atoms (CH4).

● Natural gas also contains small amounts of hydrocarbon gas liquids and non-hydrocarbon gases.

● Natural gas occurs in the tiny pores (spaces) within some formations of shale, sandstone, and other types of sedimentary rock. This is referred to as shale gas or tight gas.

● When natural gas occurs in coal deposits, it is called coalbed methane.

Properties of Natural Gas:● Natural gas is colourless, odourless, and tasteless and therefore mercaptan,

which is a chemical that smells like sulphur, is added to give natural gas a distinctly unpleasant odour.

● Mercaptan odour serves as a safety measure to help detect leaks in natural gas pipelines.

● Hydrocarbon gas liquids (HGL) are hydrocarbons that occur as gases at atmospheric pressure and as liquids under higher pressures.

● HGL has various commercial applications, chief of which are acting as diluting or thinning agent for transportation of heavy crude oil, feedstock in petrochemical plants to make chemicals, plastics, and synthetic rubber and acting as an additive for motor gasoline production.

Crude Oil and Petroleum● Location of crude oil- Underground pools or reservoirs, tiny spaces within

sedimentary rocks, and near the surface in oil sands.

● After crude oil is removed from the ground, it is sent to a refinery where different parts of the crude oil are separated into useable petroleum products.

● The components of petroleum are separated using a technique called fractional distillation.

● Petroleum products- These are fuels made from crude oil and other hydrocarbons contained in natural gas. They are also made from coal, natural gas, and biomass.

● Petroleum products include petrol, distillates such as diesel fuel and heating oil, jet fuel, petrochemical feedstocks etc.

● Gasoline is mainly used as an engine fuel in vehicles.

● Diesel fuel is used in the diesel engines found in most freight trucks, trains, buses, boats, and farm and construction vehicles

● The common everyday products derived from petroleum products or that use petroleum are Plastics, Ink, Paint, Shoe Polish, Nylons, Roof shingles, Novelty Candy, Cosmetics, Candles, Vaseline, Bug Killer, Tires, Asphalt, Crayons, Paper cups, Wax paper.

LPG and CNG

Features Liquified Petroleum Gas (LPG)

Compressed Natural Gas (CNG)

Composition A mixture of propane and butane liquefied at 15 °C and a pressure of 1.7 - 7.5 bars

Mainly methane which is compressed at a pressure of 200 to 248 bars.

Source By-product of cracking process during crude-oil refining.

Obtained from natural gas

Use Heating and cooking in homes, refrigeration, industrial, agricultural, catering and automobile fuel.

Used in automobiles.

Features Liquified Petroleum Gas (LPG)

Compressed Natural Gas (CNG)

Environmental Effects

Releases CO2 Releases lesser greenhouse gas.

Properties It is heavier than air and once it leaks it settles on the floor or low lying areas.

It disperses quickly if it spills as it is lighter than air

Safety It is highly inflammable and difficult to disperse.

It disperses easily.

Coal and Coal Combustion Products (CCP)● Coal is the fossil fuel which exists in rock form of blackish colours. ● Coal is found in natural coal beds or coal seams. ● The primary component of coal is carbon, along with nitrogen, oxygen,

Sulphur, and hydrogen. ● Coal is the primary source of fossil fuel based energy used to generate

electricity in most of the countries. ● Coal combustion products (CCP) are the materials that remain after

pulverized coal is burned to generate electricity.● They are fly ash, bottom ash, boiler slag, and flue gas desulphurization

gypsum.

Fly Ash

● During combustion of coal in coal electricity plants or furnaces, mineral impurities in the coal that include clay, feldspar, quartz, and shale fuse in suspension and exit the combustion chamber with the exhaust gases.

● This fused material rises, cools and solidifies into spherical glassy particles called fly ash.

● Fly ash is collected from the exhaust gases by separation techniques that employ electrostatic precipitators or bag filters.

● Fly ash has important commercial applications in the construction industry.

● The fine powder of fly ash resembles Portland cement but it is chemically different.

● Fly ash is used as a replacement for Portland cement which used in producing concrete.

● Concrete made with fly ash is stronger and more durable than traditional concrete.

● Furthermore, fly ash concrete is easier to pour, has a lower permeability.

● It resists alkali-silica reaction, which results in a longer life of the structure.

Bottom Ash● Bottom ash is agglomerated ash particles that are too large to be carried in

the flue gases and they stick to the furnace walls or fall at the bottom of the furnace.

● Bottom ash is grey to black in color and has a porous surface structure.

● Its commercial applications include use as an

○ Aggregate in road and pavement construction,

○ Aggregate in concrete products,

○ Feedstock in cement production etc.

Boiler Slag● Boiler slag is the molten bottom ash collected at the base of slag tap and

cyclone type furnaces.

● Boiler slag is quenched with water where it crystallizes.

● It then forms pellets which are hard and black in colour and have a shiny glasslike smooth appearance.

● Its important applications are

○ mineral filler in asphalt,

○ the raw material in concrete products,

○ component of roofing granules etc.

Flue Gas Desulfurization

● Flue gas is term given for gases exiting from flue or channels for conveying exhaust gases from a fireplace, oven, furnace etc.

● Flue gas desulfurization (FGD) gypsum is used as raw material for wallboard and concrete products.

● It is a filler material for structural applications.

● It is also used in waste stabilization and/or solidification.

Biofuels – Biodiesel

● Biodiesel is a renewable, biodegradable fuel manufactured from vegetable oils, animal fats, or recycled restaurant grease.

● In India, biodiesel is chiefly focused around Jatropha oil which is extracted from Jatropha plant species.

● It is a clean alternative to petroleum or diesel fuels.

● Biodiesel is obtained by transesterification of lipids and fats.

Transesterification process-

● The Transesterification process is the reaction of a triglyceride (fat/oil) with an alcohol to form esters and glycerol.

● During the esterification process, the triglyceride is reacted with the alcohol in the presence of a catalyst, usually a strong alkaline like sodium hydroxide.

● The alcohol reacts with the fatty acids to form the mono-alkyl ester, or biodiesel and crude glycerol.

Biofuels – Bioethanol● The primary sources of bioethanol production are the sugars found in grains

such as corn, sorghum, and barley.

● Ethanol is blended with petrol/gasoline in many countries including India.

● It is estimated that a 5% blending can result in the replacement of around 1.8 million barrels of crude oil.

● The practice of blending ethanol started in India in 2001.

● In India, ethanol is mainly derived by sugarcane molasses, which is a by-product in the conversion of sugar cane juice to sugar.

Biofuels – Biogas● Biogas is a renewable energy source and usually contains

○ Methane (55-65%),

○ Carbon dioxide (30-35%), and

○ Some hydrogen (hydrogen sulphide), nitrogen and other impurities.

● The raw material used for biogas production is organic in nature and include agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste.

● These raw materials are acted upon by anaerobic organisms like methanogenic bacteria which digest these raw materials and release biogas in the process.

Biogas Plants:

● A biogas plant is a name often given to an anaerobic digester that treats organic waste matter.

● The basic types of digesters are

○ Batch digesters and

○ Continuous digesters.

● Batch digesters are filled with a mixture of the organic wastes and water (slurry) and sealed, and emptied again when they stop producing gas.

● Continuous-load digesters are fed a daily load of slurry, with gas and digestion wastes produced continuously.

Rocket Propellants● Propellant - A chemical mixture burned to produce thrust in rockets.

It consists of high oxygen fuel or a mixture of a fuel and an oxidizer.

● Fuel- A chemical substance containing a high amount of oxygen in itself or a chemical substance that burns with an oxidizer and releases oxygen.

● Oxidizer- A chemical agent that releases oxygen for combination with a fuel.

● Mixture ratio-The ratio of oxidizer to fuel.

● Classification of Propellants- liquid, solid, or hybrids.

4. The Industries

Soaps and Detergents● In chemical terms, soaps are actually salts which are formed when an acid

(fatty acid) reacts with a base (usually NaOH or KOH).

● Manufacture of soap is done in three steps-

a. Saponification- Lye (solution of sodium hydroxide) is added to boiling fats. After several hours, a mixture of sodium salts and glycerine is formed.

b. Salting- Salt is added to the boiling solution to precipitate the soap.

c. Finishing of soap- the soap is reacted with more sodium hydroxide so that complete saponification process is completed. Soap is mixed with boiled water to dissolve excess alkali.

How soap works?

● The soap molecule has two different ends, one that is hydrophilic (polar head) that binds with water and the other that is hydrophobic (non-polar hydrocarbon tail) that binds with grease and oil.

● When greasy dirt or oil is mixed with soapy water, the soap molecules arrange themselves into tiny clusters called micelles.

Chemical Polymers● Polymers are large molecules composed of smaller units called

monomers.

● Important polymers used commercially are:

Polyvinyl chloride (PVC)-

● Rigid PVC is used in the construction of pipes as it is chemically resistant to acids, salts, bases, fats, and alcohol; doors and windows, bottles, bank cards, electric cables, clothing materials, flooring, etc.

Synthetic rubber-

● It is manufactured from petroleum products, used in the automotive industry for tire manufacturing; also used in hose pipes, rubber belts, etc.

Nylon- ● A very important synthetic polymer with variants like Nylon-6, Nylon 66

etc. ● It used in fiber making, fabric for clothes, food packaging, and toothbrush

bristles etc.Bakelite- ● Used for moldings, binding agent, varnish, protective coating, electrical and

automotive industries.Teflon- ● It is a brand name but the chemical Teflon is Polytetrafluoroethylene

(PTFE). ● PTFE is best known for providing the non-stick coating in utensils.

Neoprene-

● It is a synthetic rubber used in laptop sleeves, orthopedic braces (wrist, knee, etc.), electrical insulation, liquid and sheet applied elastomeric membranes or flashings, and automotive fan belts.

Polyethylene/Polythene-

● The non-biodegradable polymer.

Biodegradable polymers-

● Plastics derived from natural materials, such as cellulose, starch, and hydroxycarboxylic acids are more easily decomposed when exposed to oxygen, water, soil organisms and sunlight than are most petroleum- based polymers.

Explosives● Explosives are the chemical substances that are reactive and contain

potential energy (stored energy). ● Any trigger that releases the potential energy causes a sudden explosion and

heat, sound and light energies are also released.● Explosive material may be chemical explosives that release chemical

energy, or one that contains pressurized contents or may be nuclear.● High explosives detonate and the action is very rapid, almost instantaneous. ● The explosive action creates a shock wave which is highly disruptive.

Examples of high explosives- Dynamite, TNT.● Low explosives deflagrate and are burning explosives. They produce

flames. Examples- bullet propellants.

Semiconductors● In simple terms, the electrical conductivity of a semiconductor falls between

that of metals like copper and electrical insulators like glass.● Doping i.e. introduction of impurities is done in the semi-conductors to alter

the electrical conductivity.● Some well-known semiconductors are silicon and germanium.

Examples of semiconductors and their application:1. Silicon- used in photovoltaic cells, 2. Silicon carbide- used in LEDs3. Gallium nitride- magnetic semiconductor, used in spacecraft solar

panels, blue lasers.4. Gallium arsenide- high-efficiency solar cells, electronics.

Washing soda● Washing soda is sodium carbonate decahydrate, Na2CO3.10H2O● On heating, washing soda gives anhydrous sodium carbonate called soda

ash.● Sodium carbonate is used

○ In the manufacture of paper, soap, textiles, paints, etc.○ In laundry as washing soda and as a cleaning agent for domestic

purposes.○ In softening of hard water. When washing soda is dissolved in hard

water, calcium and magnesium salts which cause hardness, react with washing soda and gets precipitated as insoluble solids, thus leaving the water soft.

Baking soda● Sodium Bicarbonate is known as baking soda. ● It is a white solid and its solution is slightly alkaline which turn red litmus

blue. ● When it is heated, it decomposes with the evolution of carbon dioxide gas. ● Hence, it is used as a constituent of baking powder to soften the dough and

to aerate the drinks. ● Baking powder is a mixture of sodium bicarbonate and tartaric acid. ● Baking powder is used in aerated drinks and as an additive in foodstuff to

make it soft. ● The evolution of carbon dioxide also makes it useful for fire extinguishers.

Bleaching powder● Bleaching powder or calcium oxychloride (CaOCl2) is a yellowish white

powder with a strong smell of chlorine.

● When exposed to air, bleaching powder gives a smell of chlorine.

● It is used to bleach cotton and linen in the textile industry and washed clothes in the laundry.

● It can be also used as a disinfectant and germicide since it liberates chlorine on exposure to the atmosphere which destroys the germs.

● It is also used for disinfecting water for the same reason.

● It is also used as an oxidising agent in many chemical industries

Plaster of Paris● Plaster of Paris is calcium sulphate hemihydrate. ● It is called plaster of Paris because the gypsum which was used to get the

powder was mainly found in Paris. ● POP is prepared by heating gypsum at 373 K in rotary kilns, where it gets

partially dehydrated.● Plaster of Paris is a white powder. When it is mixed with water (1/3rd of its

mass), gypsum is obtained back. ● Setting of Plaster of Paris is accompanied by a slight expansion in volume

which makes it suitable for making casts for statues, toys, etc. ● The setting of plaster of Paris can be catalyzed by adding sodium chloride to

it.

Cement● Cement was first discovered by Joseph Aspdin in 1824.

● He called it Portland cement for the reason that the cement he discovered, resembled the limestone found in Portland.

● Portland cement consists of Lime (CaO) 60 - 70% ; Silica (SiO2) 20-25%; Alumina (Al2O3) 5-10% and Ferric oxide (Fe2O3) 2-3 %.

● When cement is mixed with water, it becomes hard over a period of time. This is called setting of cement.

● Gypsum is often added to Portland cement to prevent early hardening or "flash setting", allowing a longer working time.

Glass● The approximate composition of ordinary glass is given by the formula,

Na2O. CaO.6SiO2.

● The raw materials required for the manufacture of ordinary glass are sodium carbonate, calcium carbonate, and silica.

● The slow and uniform cooling of glass is called Annealing.

● If the glass is cooled rapidly, it becomes very brittle and cracks easily and if it is cooled very slowly, it becomes opaque. Therefore, it should be cooled neither very slowly nor very quickly.

Zeolites● Zeolite is a complex salt called sodium aluminum silicate commonly used

as commercial adsorbents.

● Zeolites are widely used in industry for water purification, as catalysts, for the preparation of advanced materials and in nuclear reprocessing.

● Their biggest use is in the production of laundry detergents. They are also used in medicine and in agriculture.

● The temporary hardness of water can be removed easily by boiling water or by adding washing soda (Sodium Carbonate-hydrated).

● Permanent hardness cannot be removed by merely boiling or adding washing soda. Zeolite is used to remove permanent hardness in water.

Organic Compounds- Alkanes● Alkanes have a simple single carbon to carbon bond.

● They are also called saturated hydrocarbons because the valency of carbon atoms is complete or saturated.

● Alkanes with long carbon chains are also known as paraffin.

● Methane (CH4 ) is the simplest alkane.

● Methanogens are the bacteria that are found in the guts of cows and produce large quantities of methane by the metabolism of carbon dioxide.

● Methane and ethane are the main components of natural gas.

● Propane and butane can be liquefied at fairly low pressures, and are well known as liquefied petroleum gas (LPG).

● Propane is also used as a fuel for cars.

● Butane is used in disposable cigarette lighters.

● And the two alkanes are used as propellants in aerosol sprays.

● From pentane to octane the alkanes are used as fuels in internal combustion engines, as they evaporate easily on entry into the combustion chamber.

● The musk of the Musk deer contains Cycloalkanes with 14 to 18 carbon atoms.

● Alkanes from nonane to hexadecane are liquids of higher viscosity, less and less suitable for use in gasoline.

● They form instead of the major part of diesel and aviation fuel.

● Many solid alkanes find use as paraffin wax, for example, in candles. This should not be confused however with true wax, which consists primarily of esters.

● Alkanes with a chain length of approximately 35 or more carbon atoms are found in bitumen, used, for example, in road surfacing.

Organic compounds- Alkenes● Alkenes have at least one carbon to carbon double bond.

● The physical properties of alkenes are comparable with those of alkanes.

● The main differences between the two are that the acidity levels of alkenes are much higher than that of alkanes.

● Alkenes are extremely important in the manufacture of plastics. All plastics are in some way related to alkenes.

● The names of some plastics (Polythene, Polypropene), relate to their alkene partners.

● Lower alkenes are used as fuel, for the manufacture of a wide variety of polymers, e.g., polyethylene, polyvinyl chloride (PVC) and teflon etc.

● And it is used as raw material for the manufacture of industrial chemicals such as alcohols, aldehydes, etc.

● Besides, alkenes also used

○ For artificial ripening of fruits,

○ As a general anesthetic,

○ For making poisonous mustard gas (War gas) and

○ For making ethylene-oxygen flame.

Organic compounds- Alcohols● Alcohols are compounds which contain carbon, hydrogen, and oxygen.

Applications of Alcohols:

1. Alcoholic beverages, typically contain 5% to 40% ethanol by volume.

2. Antifreeze: A 50% v/v (by volume) solution of ethylene glycol in water is commonly used as an antifreeze.

3. Antiseptics: Ethanol can be used as an antiseptic to disinfect the skin before injections are given, often along with iodine.

4. Soaps: Alcohol-based soaps are convenient because they do not require drying due to the volatility of the compound.

5. Sanitizers: Alcohol-based gels have become common as hand sanitizers.

6. Fuels: Ethanol and methanol can be used as alcohol fuels.

7. Preservative: Alcohol is often used as a preservative for specimens in the fields of science and medicine.

8. Because of its relatively low toxicity compared with other alcohols and ability to dissolve non-polar substances, ethanol can be used as a solvent in medical drugs, perfumes, and vegetable essences such as vanilla.

Organic compounds-Ethanol● Alcohol is produced by the fermentation of sugar present in molasses

derived from the sugar industry. ● In our daily life the change of milk into curd, souring of kneaded flour,

etc., are examples of fermentation. Applications:1. Manufacture of paints, varnishes, organic compounds like ether,

chloroform, and iodoform. 2. As an antiseptic to sterilize wounds and syringes in hospitals and

dispensaries. 3. In alcoholic drinks (beverages) like whiskey, wine, beer, and other liquors.

Organic compounds- Methanol● Methanol is mostly converted to formaldehyde, and from there into

products as diverse as plastics, plywood, paints, explosives, and permanent press textiles.

● Dimethyl ether (DME) which is derived from methanol has replaced chlorofluorocarbons as an aerosol spray propellant.

● As a denaturant for ethanol ("denatured alcohol" or "methylated spirit"), because methanol is poisonous for the nervous system. It is to discourage consumption of bootlegged liquor which causes several deaths.

● As an antifreeze in pipelines and windshield washer fluid.

Organic compounds- Formaldehyde● The formic acid derived from formaldehyde is found in the venom of bee

and ant stings and is used as a preservative and antibacterial agent in livestock feed.

● An aqueous solution of formaldehyde called Formalin is a powerful disinfectant and antiseptic. It is used for preserving dead bodies, biological specimens and sterilising surgical instruments.

● Manufacture of paints and dyes. ● It is mixed with phenol in the manufacture of bakelite, a plastic which is

used for making electrical switches. ● Formaldehyde is condensed with ammonia to produce urotropine which is

an important medicine in urinary ailments.

Organic compounds- Acetaldehyde● Acetaldehyde or ethanal occurs naturally in coffee, bread, and ripe fruit,

and is produced by plants as part of their normal metabolism.

● It causes hangovers from alcohol consumption.

● Acetaldehyde is a probable or possible carcinogen in humans.

Organic compounds- Acetones

● Acetone is a colorless, inflammable, volatile liquid with a characteristic pleasant smell.

● Acetone is a good solvent for most plastics and synthetic fibers including those used in laboratory bottles made of polystyrene, polycarbonate and some types of polypropylene.

● It is used as a volatile component of some paints and varnishes.

● It is also used in the synthesis of rubber, in the manufacture of artificial leather, and to clean and dry the parts of precious equipment and as a nail polish remover.

Organic compounds- Acetic Acid● Acetic Acid is mainly used in the production of cellulose acetate mainly for

photographic film and polyvinyl acetate for wood glue, as well as synthetic fibers and fabrics.

● In the food industry, acetic acid is used as an acidity regulator and as a condiment.

● The major use of acetic acid is for the production of vinyl acetate monomer (VAM).

● VAM is further polymerized to polyvinyl acetate or to other polymers, which are components in paints and adhesives.

● The acetates of metals such as Sodium, Magnesium etc. have wide usage such as preservatives, food industry, fungicides, dyes etc.

Thank You!