Carbon and its compound

1. Soaps are formed by the saponification of

(a) Alcohols (b) simple ester (c) carboxylic acids (d) glycerides

2. The functional group of butanone is

(a) Carboxyl (b) ketonic (c) aldehydic (d) alcoholic

3. Enzyme which converts starch into glucose is

(a) Zymase (b) Maltase (c) Diastase (d) Invertase

4. The first compound to be prepared in the laboratory was

(a) Methane (b) Ethyl alcohol (c) acetic acid (d) Urea.

5. The IUPAC name of 3CH CHO is

(a) Acetaldehyde (b) Formaldehyde (c) Methyl formaldehyde (d) Ethanal.

6.

Name the following compounds. (a) |

H

H C O− = (b) 3 2CH CH Cl− −

7. Define soaps?

8. Name the second member of alkynes family Give its structure?

9. Give a chemical test to distinguish between Ethane and ethane.

10. Complete the following reaction

(i) 422 2 2 = + →H SOH C CH H O

(ii) 2HC CH Br≡ + →

(iii) 2 5C H OH Na+ →

11.

What is the role of concentrated 2 4H SO in the esterification reaction?

12. What will be the formula and electron dot structure of cyclopentane ?

13. Draw the structures of the following compounds

14. Define fermentation. Name the enzyme which converts

(a) milk into curd (yogurt)

(b) Cane sugar into glucose and fructose

(c) glucose into ethanol

(a) Ethanoic acid

(b) Bromopentane

(c) Butanone

ANSWERS

Ans1. (d) Ans2. (b) Ans3. (a) Ans4. (d) Ans5. (d)

Ans6. (a) Methanol

(b) Chloroethane

Ans7. Soaps are the sodium or potassium salts of long chain fatty acids. These are

represented by RCOONa or RCOOR

Ans8. The second member of the alkyne family is propyne. Its structural formula is

3CH C CH− ≡

Ans9. Ethene decolorizes the yellow colour of bromine water while ethane does not.

Ans10. (i) 422 2 2 3 2 = + → − −H SOH C CH H O CH CH OH

(ii) | |

2| |

2

Br Br

Br Br

HC CH Br H C C H≡ + → − − −

(iii) 2 5 2 5 22 2 2C H OH Na C H ONa H+ → +

Ans11. In esterification reaction a carboxylic acid reacts with alcohol to form ester and

water in the presence of concentrated sulphuric acid. This reaction is reversible

and this reverse reaction is called ester hydrolysis.

Concentrated sulphuric acid being a strong dehydrating agent removes water

from the reaction mixture. As a result, the reaction proceeds only is the forward

direction to form ester.

2 4 2

Acid Alcohol Ester

+ → +conc H SoRCOOH ROH RCOOR H O

Ans12. It is a cyclic compound with formula 5 12C H . The structure of the compound is

represented as

C

C

C

C

C

H

H

HH

H

H

H

H

H

H

Ans13. (a) ||O

H

HH C C OH− − − Ethanoic acid

(b) 3 2 2 2 2− − − − −CH CH CH CH CH Br Bromopentane

(c) ||

3 2 3− − −O

H C C CH CH Butanone

Ans14. The preparation of ethyl alcohol from sugar ( )12 22 11C H O is known as

fermentation.

(a) Lactase converts milk into curd

(b) Invertase converts cane sugar into glucose and fructose

(c) Zymase converts glucose into ethanol.

Carbon and its compound

1. Rectified spirit is

(a) 50% ethanol (b) 80% ethanol

(c) 95% ethanol (d) 40 to 50%

2. Dilute alkaline KMnO4 solution is

(a) an oxidising agent (b) a reducing agent

(c) a bleaching agent (d) none of these

3. The by product in soap industry is

(a) Isoprene (b) Ethylene glycol

(c) glycerol (d) butane

4. An example of soap is

(a) 15 31C H COONa (b) 3CH COONa

(c) 6 5C H COONa (d) 17 35 3C H OSO Na

5. The number of C-H bonds is ethane C2H6 molecule are

(a) 4 (b) 6

(c) 8 (d) 10

6. Write the structures of

(i) Ethanoic acid (ii) Hex anal

7. Name the following compounds

(a) 3 0H

CH C− = (b) 3 2CH CH OH− −

8. Which organic compound is added to make ethanol unfit for drinking purposes? What is the name of the mixture formed?

9. Write a test to identify the presence of ethanoic acid?

10. Give names of the following

(a) An aldehyde derived from ethane

(b) Ketone derived from butane

(c) Compound obtained by the oxidation of ethanol by chromic anhydride

11. What is meant by denatured alcohol? What is the need to denature alcohol?

12. Write chemical equations of the reactions of ethanoic acid with

(a) Sodium (b) Sodium carbonate

(c) Ethanol (d) The presence of conc H2So4

13. Complete the reaction and names of the products formed

(i) 3 + →heatCH COOH NaOH

(ii) 2 5 24

+ alkalineC H OH O

KMnO

(iii) 2 4 3 2 5 4+ →Conc H SOCH COOH C H O

14. (a) Name the gas evolved during fermentation process?

(b) What role is played by yeast in the conversion of cane sugar (C12H22O11) to

ethanol?

(c) How may the following be obtained from pure ethanol? Express chemical

reactions by the chemical equations.

(i) Sodium ethoxide (ii) Ethyl ethanoate (iii) Ethanal

ANSWERS

Ans1. (c) Ans2. (a) Ans3. (c) Ans4. (a) Ans5. (b)

Ans5. (b)

Ans6. (i) CH3-||O

C -on

(ii) CH3-CH2-CH2-CH2-CH2-||O

C -H

Ans7. (a) Ethanal

(b) Ethanol

Ans8. Methanol which is highly poisonous is added to make ethanol unfit for drinking

purpose. The mixture is called methylated spirit or denatured alcohol.

Ans9. Dip a strip of blue litmus paper in the solution of ethanoic acid. Its colour will

change to red.

Ans10. (a) Ethanal (CH3CHO)

(b) Butanone (CH3COCH2CH3)

(c) Ethanal (CH3CHO)

Ans11. Ethyl alcohol which contains small amount of methyl alcohol or copper sulphate is

called denatured alcohol. The purpose of denaturing of alcohol is to make it unfit

for drinking purposes.

Ans12. (i) 2CH3COOH+2Na → 2CH3COONa+H2

(Sod. Ethanoate)

(ii) 2CH3COOH+Na2CO3 → 2CH3COONa+CO2+H2O

(Sod. Ethanoate)

(iii) CH3COOH+C2H5OH 2 4 →conc H SoCH3COOC2H5

(Ethyl ethanoate)

Ans13. (i) CH3COOH+NaOH →Heat CH3COONa+H2O

(Sod. Ethanoate)

(ii) C2H5OH+O2alkaline

KMnOHCH3COOH+H2

(Ethanoic acid)

(iii) CH3COOH+C2H5OH 2.→Conc H SolCH3COOC2H5+H2O

(Ethylethanoate)

Ans14. (a) CO2 gas is evolved accompanied by brisk effervescence.

(b) Yeast is the source of enzymes invertase and zymase needed for fermentation.

(c) (i) 2C2H5OH+2Na → 2C2H5ONa+H2

(ii) C2H5OH+CH3COOH 2 4→H SOCH3COOC2H5+H2O

(Ethyl ethanoate)

(iii) C2H5OH+1

2O2

3

3

CrO is

Ch COOHCH3CHO+H2O

Carbon and its compound

1. An unknown compound has the smell of vinegar. Identify it.

2. Out of butter and groundnut oil which is unsaturated in nature.

3. Which has triple bond, 2 4 3 4 3 6, ,C H C H C H

4. Which substance is added for the denaturation of ethyl alcohol

5. Which ions are responsible for making water hard?

6. Why carbon and its compounds used as fuels in most cases?

7. A compound X has the molecular formula 3 6C H O with structural formula

3 2CH CH CHO . Give its IUPAC name. Can another compound have the same

molecular formula? Give the structure and IUPAC name of that compound also.

8. Why CHO group cannot be present in the middle of the carbon atom chain?

9. Two carbon atoms cannot be linked to each other by more three covalent bonds. Why?

10. Write three difference between ethanol and ethanoic acid on the basis of chemical properties?

11. Given a chemical test to distinguish between

(i) Ethane and ethene (ii) Ethanol and ethanoic acid (iii) Soaps and Detergents

12. Name the functional groups present in the following compounds?

(i) 3 2 2− − −CH CH CH OH (ii) 3 2 2− − −CH CH CH COOH (iii) 3 2CH CH CHO− −

13. What are esters? Write an equation to show the formation of ester?

14. (a) Why does carbon form largest number of compounds?

(b) Why are some of these called saturated and other unsaturated compounds?

(c) Which of these two is more reactive?

(d) Write the names of the following compounds

(i) 2 2CH CH Br− − (ii) 3 − − − − ≡ −CH CH CH CH C C H

ANSWERSAns1. Acetic acid Ans2. Groundnut oil Ans3. 3 4C H Ans4. Methyl Alcohol

Ans5. 2Ca + and 2Mg +

Ans6. Carbon burns in oxygen or air to form 2CO gas. This reaction is highly

exothermic that is why different form of coals are used as fuels

Ans7. The IUPAC name of X is propanal.

Another similar compound is Y is.

||

3 3− −O

CH C CH (Propanone)

X and Y are related to each other as functional isomers.

Ans8. The CHO group is a terminal functional group since three valencies of the C-

atom are already satisfied, so this group cannot be present in the middle of the

chain.

Ans9. When two carbon atoms are to linked by four covalent bonds their nuclei come

so close to one another that the force of repulsion between them will push these

apart. As a result, a stable molecule will not be formed.

Ans10. (i) On adding a small amount of 3NaHCO to ethanoic acid CO2 gas is evolved

with brisk effervescence and no such reaction takes place in case of ethanol

3 3 3 2 2+ → + +CH COOH NaHCO CH COONa CO H O

(ii) Ethanol is neutral so does not bring any change in the colour of litmus paper

but ethanoic acid is acidic and changes the colour of a blue litmus strip to

red when dipped in it.

(iii) Ethanoic acid reacts with NaOH and KOH to form salt and water where as

ethanol fails to react.

3 3 2

3 3 2

+ → ++ → +

CH COOH NaOH CH COONa H O

CH COOH KOH CH COOK H O

Ans11. (i) Ethane decolorizes the yellow colour of bromine while ethane does not.

(ii) Ethanoic acid gives a brisk effervescence with sodium hydrogen carbonate

while ethanol does not.

(iii) Soaps form curdy white precipitate or scum with hard water while

detergents do not form any precipitate.

Ans12. (i) ( )−OH ol

(ii) ( ) COOH oic acid−

(iii) ( )CHO al−

Ans13. Esters are pleasant smelling compounds and are commonly used as flavoring

agents. Monocarboxylic acids react with alcohol to form esters and water. This

reaction is called as esterification

2 3 3 3 3 2

Methyl Ethonoate (Ester)

+ → +conc H SOHCH COOH CH OH CH COOCH H O

2 4.3 2 5 3 2 5 2

Ethyl Ethanoate (Ester)

+ → +Conc H SOCH COOH C H OH CH COOC H H O

Ans14. (a) Carbon forms large number of compounds called organic compounds due to

the self linking property called catenation.

(b) Compounds which has only C-C (single bond) present are saturated

compounds whose as those compounds which has C=C (double bond) or

C ≡ C (triple) bond is present are called unsaturated compounds.

(c) Unsaturated compounds are more reactive than saturated compounds

(d) (i) Bromoethane

(ii) Hex-1-yne

Carbon and its compound

1. The odour of acetic acid resembles that of

(a) Rose

(b) Burning Plastic

(c) Vinegar

(d) Kerosene

2. Diamond is not a good conductor of electricity because

(a) is very hard

(b) Its structure is very compact

(c) It is not soluble in water

(d) It has no free electrons to conduct electric current.

3. Alcohols can be produced by the hydration of

(a) Alkenes

(b) alkynes

(c) alkenes

(d) acids

4. The IUPAC name of CH3CHO is

(a) Acetaldehyde

(b) formaldehyde

(c) methyl formaldehyde

(d) ethanol

5. IUPAC name of first member of homologous series of ketones is

(a) Ethanone

(b) methanone

(c) Propanone

(d) Butanone

6. What are the properties of carbon which lead to the huge number of carbon compounds we see around us?

7. Name the following compound

(a) CH3-CH2-Br

(b) 3 2 2

CH CH CH C CH− − − ≡

8. Why is conversion of ethanol into ethanoic acid an oxidation reaction?

9. A mixture of ethyne and oxygen is used for welding. Can you justify why a mixture of ethyne and air is not-used?

10. What is a homologous series? State any two characteristics of homologous series?

11. Give the structural formulas for

(i) Methyl Ethanote

(ii) Ethyl ethanoate

Write two uses of Ester?

12. What are enzymes? Name the enzymes required for the fermentation of sugarcane to ethanol?

13. The formula of an ester is C3H7COOC2H5 write the formulae of the acid and alcohol from which the ester is prepared.

14. An organic compound A is widely used as a preservative in pickles and has a

molecular formula C2H4O2. This compound reacts with ethanol to form a sweet

smelling compound B.

(a) Identify the compound A.

(b) Write the chemical equation for its reaction with ethanol to form compound B.

(c) How can we get compound A back from B.

(d) Name the process and write the corresponding chemical equation.

(e) Which gas is produced when compound A reacts with washing soda? Write the chemical equation?

ANSWERS

Ans1. (c) Ans2. (d) Ans3. (a) Ans4. (d) Ans5. (c)

Ans6. (i) Self linking property called catenation

(ii) Carbon is tetravalent and can readily unite with atoms like hydrogen, oxygen

etc by electron sharing

Ans7. (i) Bromoethane

(ii) Hex-1- yne

Ans8. Ethanoic acid has one O2, atom more and two hydrogen atoms less then ethanol.

And loss of hydrogen is known as oxidation and gain of oxygen is known as

oxidation. Therefore it is an oxidation reaction.

Ans9. When ethyne is burnt in oxygen, large quantity of heat and light is produced. The

heat evolved can be used for gas welding which is used for welding broken pieces

of articles. As air contains mixture of nitrogen and oxygen and nitrogen which is

more in amount does not support combustion. Therefore it is always better to use

oxygen for the combustion of ethyne.

Ans10. A series of similarly constituted compounds in which the members present have

the same functional group, same chemical properties and any two successive

members is a particular series differ in their molecular formula by CH2 group.

(i) Same functional group

(ii) Same chemical properties.

Ans11. (i) ||

3− −O

H C OCH

(ii) 3 2 5CH COOC H

Uses of esters:

(1) Esters have pleasant smell. These are used as flavouring agents and also

in perfumes.

(2) Esters of glycerol know as triglycerides are used in the manufacture of

soaps. This reaction is called saponification reaction.

Ans12. Enzymes are the biocatalysts which catalyse the reactions in the living beings. In

the process of fermentation of sugar into ethanol, two enzymes are used.

12 22 11 2 6 12 6 6 12 6 + +����������

C H O H O Invertase C H O C H O

Sugar glucose fructose

6 12 6 2 5 2 2C H OH+2COC H O Zymase���������

Glucose and Fructose

Ans13. The molecular formula for acid is C3H7COOH (Butanoic acid) and for alcohol is

C2H5OH (Ethyl alcohol)

3 7 2 5 3 7 2 5 2 + + →C H COOH C H OH C H COOC H H O

Butanoic acid Ethyl alcohol Butanoate (Ester)

Ans14. (a) Compound A is ethanoic acid (CH3COOH)

(b) CH3COOH + C2H5OH → CH3COOC2H5+H2O

Ethanoic acid Ethyl Ethanoate (Ester)

(c) CH3COOC2H5+H2O H +����

CH3COOH +C2H5OH

Ethanoic acid

(d) The process is known as ester hydrolysis.

(e) CO2 is produced with effervescence when compound A reacts with washing

soda which is chemically Na2CO3

2CH3COOH+Na2CO3 → 2CH3COONa+H2O+CO2