Applications of Colloids

Q.

Wood charcoal is used to decolourise sugar because it

[CPMT 2002]

1. Absorbs decolorised material

2. Reduces coloured material

3. Adsorbs coloured material

4. None of these

Q. Which of the following is/are the functions of an emulsifying agent?

1. It prevents emulsions from splitting or coagulating
2. It increases the stability of emulsions
3. An emulsifying agent forms an interfacial film between the dispersed phase and the dispersion medium
4. An emulsifying agent is soluble in both the dispersion phase and the dispersion medium

Q. Glutamic acid $H_{2}N-CH\left(C{H}_{2}C{H}_{2}COOH\right)-COOHN$ has $p{K}_{a1}(\alpha -COOH)=2.2,pKa2\left(RgroupCOOH\right)=4.3$. The isoelectric point of glutamic acid is

1. 5.9
2. 7
3. 3.2
4. 10.2

Q.

Which of the following electrolytes is least effective in causing flocculation of

ferric hydroxide sol

[MNR 1991; UPSEAT 1999]

1. 
2. 
3. 
4. 

Q. Two open beakers one containing a solvent and the other containing a mixture of that solvent with a non volatile solute are together sealed in a container. Over time:

1. The volume of the solution decreases and the volume of the solvant increases.
2. The volume of the solution and the solvent does not change
3. The volume of the solution increases and the volume of the solvent decreases
4. The volume of the solution does not change and the volume of the solvent decreases

Q.

Why lyophilic colloids are more stable than lyophobic colloids?

Q.

Give the reason why a delta is formed at the meeting point of seawater and river water.

Q.

Which one of the following statements is correct :

i) Brownian movement is more pronounced for smaller particles than for bigger ones

ii) Sols of metal sulphides are lyophilic

iii) Schulze-Hardey law states, the bigger the size of the ion, the greater is its coagulating power

iv) One would be expect charcoal to adsorb chlorine more strongly hydrogen sulphide

1. i, iii & iv
2. ii, iv
3. i, iii
4. i , iii

Q.

Which of the following is the weakest acid?

1. Cl₃CCOOH

2. Cl₂CHCOOH

3. ClCH₂COOH

4. CH₃COOH

Q.

Foam rubber is an example of which type of colloid?

1. sol

2. solid foam

3. solid sol

4. foam

Q.

Given below are a few electrolytes, indicate which one among them will bring about the coagulation of a gold sol. quickest and in the least of concentration?

1. MgSO4
2. K4[Fe(CN)6]
3. Al2(SO4)3
4. NaCl

Q. The correct order of coagulating power of the given cations in the coagulation of a negative sol, is:

1. $A{l}^{3+}>B{a}^{2+}>N{a}^{+}$
2. $N{a}^{+}>B{a}^{2+}>A{l}^{3+}$
3. $N{a}^{+}>A{l}^{3+}>B{a}^{2+}$
4. $B{a}^{2+}>A{l}^{3+}>N{a}^{+}$

Q.

_________ gas is used to disinfect the water in the swimming pool.

Q. The coagulation of $10{\text{cm}}^3$ of Gold sol by $1\text{mL}$ $10\%$ $NaCl$ solution is completely prevented by addition of $0.25\text{g}$ of starch to it. The gold number of starch is:

Q.

Grignard reagent reacts with carbon dioxide to form:

1. Salts of carboxylic acids

2. 2, 2-Dimethylpropionaldehyde

3. Benzaldehyde

4. 2-methylpropionaldehyde

Q. Which temperature is related to micelle formation?

1. Critical temperature
2. Inversion temperature
3. Reduced temperature
4. Kraft temperature

Q.

What is emulsion in chemistry?

Q. ${10}^{-4}$ g of gelatin is required to be added to 100 $c{m}^3$ of a standard gold solution to just prevent its precipitation by addition of 1 $c{m}^3$ of 10% NaCl solution to it. Hence the gold number of gelatin is

1. 0.01
2. 10
3. 1
4. 0.1

Q.

How is sol different from emulsion?

Q.

Which of the following electrolytes is most effective in the coagulation of gold solution [KCET 1996]

1. 

2. 
   

3. 
   

4. 

Q.

How does the precipitation of colloidal smoke take place in the Cottrell precipitator?

Q. What is a protective colloid ?

Q. The following graph is plotted for the same solute at different concentrations in a given solvent.

The concentration of the solution are in the order:

1. I < II > III
2. III > II > I
3. II > I > III
4. II > III > I

Q.

Purple of Cassius is

1. Colloidal solution of platinum

2. Oxyacids of gold

3. Colloidal solution of gold

4. Colloidal solution of Sulphur

Q. Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration.

Q.

Which of the following forms a colloidal solution in water?

1. C₆H₁₂O₆

2. Ba(NO₃)₂

3. Starch

4. NaCl

Q. Charge of nos ligand

Q.

Which of the following are macromolecular colloids?

1. Soap

2. Starch

3. Cellulose

4. Both (B) and (C)

Q. Which of the following are colloids?

1. Chlorophyll
2. Egg
3. Ruby glass
4. Milk

Q.

Name the lyophobic colloid present in the milk.