chemistry stoichiometry & colloids stoichiometry & colloids

CHEMISTRYCHEMISTRY

STOICHIOMETRY & COLLOIDSSTOICHIOMETRY & COLLOIDS

The equivalent mass of MnSOThe equivalent mass of MnSO44 is half of its is half of its molecular mass when it is converted into-molecular mass when it is converted into-

1. Mn1. Mn22OO3 3

2. KMnO2. KMnO44

3. MnO3. MnO22

4. K4. K22MnOMnO44

Answer Answer : - 3: - 3rdrd option option

MnMn2+ 2+ →→ Mn Mn4+4+

Answer Answer :- Option No 1 :- Option No 1

E=32.79E=32.79

1.981.98 = = E E

1.92 31.81.92 31.8

1.98 g of Zn displaces 1.92 g of copper from CuSo4 solution. So the Equivalent mass of Zinc is : - (Equivalent Mass of Cu = 31.8)

1. 32.79 2. 32.3

3. 65.5

4. 63.5

AnswerAnswer:- Option No3:- Option No3 Atomic Mass = Mass of atom x N Atomic Mass = Mass of atom x N44

= 6.642x10 = 6.642x10 -26-26 x 6.022x10 x 6.022x102323

= 0.040 kg = 40 g = 0.040 kg = 40 g = at Mass of calcium = 40 = at Mass of calcium = 40

The element whose atom has a mass of 6.642 x 10 -26 Kg is –

1. Silver

2. Zinc

3. Calcium

4. Boron

AnswerAnswer : - Option No 2 : - Option No 2

6.022x106.022x102323

The number of molecules in 16 g of methane is 1.3.0 x 1023

2. 6.022x1023

3. 16/6.022x 1023

4. 16 3.0 x 1023

AnswerAnswer : - Option No4 : - Option No4

19.7 kg of gold was recovered from a smuggler. So the number of atoms of gold recovered is ( At . Mass of Au = 197) 1. 100

2. 6.022x1023

3. 6.022x1024

4. 6.022x1025

AnswerAnswer : - Option no 4 : - Option no 4

BacoBaco33→→Bao+CoBao+Co22

197g197g→→22.4 L22.4 L 9.85g9.85g→→? – ? – 9.85x 22.49.85x 22.4 197197 = 1.12L= 1.12L

Assuming fully decomposed the volume of CO2 released at STP when 9.85 g of BaCo3 will be ( At Mass of Ba=137)

1. 0.84L

2. 2.24 L

3. 4.06L

4. 1.12L

Answer Answer : - Option No 3 : - Option No 3

The Indicator used in titrating oxalic acid with caustic soda solution is

1. Methyl Orange

2. Methyl Red

3. phenolphthalein

4. Diphenylamine


NN22+3H+3H22→→2NH2NH33

4: 2 or 2:14: 2 or 2:1

If a Mixture containing 3 moles of Hydrogen and 1 mole of Nitrogen is converted completely into ammonia, the ratio of initial and final volumes at the same temperature and pressure would be

1. 1:2

2. 2:1

3. 1:3

4. 3:1

Answer Answer : - Option No1: - Option No1

M = M = mass/dm3 mass/dm3

G.mol. MassG.mol. Mass

2020 = 0.5 = 0.5

4040

The Molarity of a solution containing 5g of NaoH in 250cm3 solution is

1. 0.5

2. 0.1

3. 3. 2

4. 4. 1

Answer : - Option no 1Answer : - Option no 1

NN11VV11 = N = N22VV22 100x0.5 = V 100x0.5 = V22 x0.1 i.e. V x0.1 i.e. V22=500cm=500cm33

Vol of water to be added 500-100= 400cmVol of water to be added 500-100= 400cm33

The volume of water to be added to 100cm3 of 0.5N H2 SO4 to get decinormal solution is –

1. 400cm3

2. 500cm3

3. 450cm3

4. 100cm3

Answer : - Option number 4Answer : - Option number 4

2Mg +O2Mg +O22→→2MgO 48g Mg reacts with 32g of O22MgO 48g Mg reacts with 32g of O2

48g 32g 2x40g so that 30g Mg, 48g 32g 2x40g so that 30g Mg, 30x3230x32 = 20g of O2 = 20g of O2 4848Mass of MgO = 30+20=50Mass of MgO = 30+20=50Mass of unreacted O2 = 30 – 20=10Mass of unreacted O2 = 30 – 20=10

30g of Magnesium and 30g of oxygen are reacted and the residual mixture contains

1.60g of Mg only

2. 40g of MgO and 20g of O2




20 cm3 of 0.05N HCl and 35cm3 of 0.01N NaOH are mixed. The resulting solution will be-

1.Be Neutral

2. Be basic

3. Turn phenolphthalein into pink

4. Turn methyl orange red


When a small amount of FeCl3 is added to a freshly precipitated Fe(OH)3, a reddish brown colloidal solution is obtained. This phenomenon is know as-

1.Dialysis

2. Peptisation

3. Protection

4. Dissolution

AnswerAnswer : - Option No 2 : - Option No 2

In the preparation of AgI solution, the excess of potassium iodide solution is added to silver nitrate solution. The colloidal solution will have

1. Positive charge

2. Negative charge

3. No charge

4. Both positive and negative charge

AnswerAnswer : - Option number 2 : - Option number 2

In a colloidal system , total number of phases is/are

1. One

2. Two

3. Three 4. Eight


Colloidal particles carry some charge. This can be show by

1.Electrophoresis

2. Dialysis

3. Tyndall effect

4. Brownian Movement.

A metallic oxide has formula MO, If the atomic mass of the metal is 24. the Equivalent mass of the metal is

1) 12. 2) 24.

3) 36. 4) 18.

Answer : - Option No1

One mole of H2SO4 in a dm3 forms

1) 2N Solution. 2) IN Solution.

3) 0.105N Solution. 4) 0.25N Solution.


The volume of 0.5N NaOH which neutralizes 6.3g of oxalic acid crystals? 1)100cm3. 2)20cm3.

3)200cm3. 4)400cm3. Answer : - Option No3

0.5NxV/1000=6.3/630.5NxV/1000=6.3/63

Surface tension of hydrophilic sols is? 1) Lower than water. 2) Higher than water. 3) Equal to water. 4) Higher or lower than

water.


Lyophillic sols are more stable than lyophobic sols because?

1) The colloidal particles have positive charge.

2) The colloidal particles have no charge.

3) The colloidal particles are solvated.

4) There is strong electrostatic repulsion.


Colloidal particles can be separated from those of particles of molecular dimensions by

1) Dialysis. 2) Coagulation 3) Electrophoresis. 4) pyrolysis.

Answer : - Option No 1

An example of micelle is

1) Sodium stearate. 2) Gold sol.

3) Nacl Solution. 4) Ruby Glass.


Gelatin is mostly used in making ice

creams in order to

1) Prevent making of a colloid.

2) Stabilize the colloid and prevent crystallizations.

3) Develop a taste.

4) Enrich the aroma. Answer : - Option No 2

Cloud bursts due to 1) Attraction towards the electrical charge on the earth.

2) Large amount of water present in the cloud.

3) Dense cloud present in the upper atmosphere.

4) Mutual discharge of oppositely charged clouds resulting in the coagulation.


Gold numbers of Gelatin(I), Gum arabic (II), egg albumin (III) are 0.005,0.20 and 0.18 respectively. Arrange these in decreasing order of protective power.

1) I > II > III. 2) I > III > II.

3) II > III > I. 4) III > II > I.


Which of the following least effective in causing flocculation of ferric hydroxide sol?

1) K4[Fe(CN)6] 2) Na2CrO4

3) KBr

4) Na2so4


The Method usually employed for the destruction of a colloidal sol is

1) Addition of electrolytes.

2) Diffusion through animal membrane.

3) Condensation

4) Dialysis.


Butter is a colloid formed when

1) Fat is dispersed in water.

2) Water is dispersed in fat.

3) Fat globules are dispersed in water and milk.

4) Fat globules are dispersed in water and curds.


If the dispersed phase is a liquid and the dispersed medium is solid, the colloid is known as a/an

1) Sol. 2) emulsion. 3) gel. 4) Foam.


In case of small cuts, bleeding is stopped by applying potash alum, here alum acts as

1) Fungicide.

2) Disinfectant.

3) Germicide.

4) coagulating agent.


The simplest way to check whether a system is colloidal is by

1) Tyndall effect. 2) Brownian movement.

3) Electro dialysis. 4) Finding out particle size.


A liquid is found to scatter a light beam but leaves no residue on passing through the filter paper.

1) a suspension.

2) An oil.

3) a colloidal sol.

4) a true solution.


Dialysis can separate

1) Glucose and Fructose.

2) Glucose and Sucrose.

3) Glucose and Nacl.

4) Glucose and protein.


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