Applications of Colloids

Q.

Starch dispersed in hot water is an example of

1. Emulsion

2. Hydrophobic sol

3. Lyophilic sol

4. Associated colloid

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.

Which is not colloidal [CPMT 1984; MP PET 1989, 91]

1. Chlorophyll

2. Egg

3. Ruby glass

4. Milk

Q.

Gold number is [MP PET/PMT 1988]

1. The number of mg of lyophilic colloid which should be added to 10 ml of ferric hydroxide sol so as to prevent its coagulation by the addition of 1 ml of 10% sodium chloride solution

2. The number of mg of lyophilic colloid which should be added to 10 ml of standard gold sol so as to prevent its coagulation by the addition of 1 ml of 10%

3. The mg of gold salt to be added to a lyophilic colloid to coagulate it

4. The mg of an electrolyte required to coagulate a colloid

Q.

Alum is used to purify water since it acts as

1. Bactericide

2. De-odorant

3. Softener

4. Coagulant

Q.

Which of the following is most effective in coagulating a ferric hydroxide sol [MP PET 1993, 97; M

1. 
2. 
3. 
4. 

Q.

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

1. 

2. 
   

3. 
   

4. 

Q.

Alum is used to purify water since it acts as

1. Bactericide

2. De-odorant

3. Softener

4. Coagulant

Q. Which of the following are applications of colloids?

1. Formation of delta
2. Cottrel precipitator
3. Alloying
4. Ideal gas equation

Q.

On adding $FeC{l}_3$ solution into NaOH solution, a possitively charged colloidal sol is obtained when they are in

1. 100 mL of 0.1 M $FeC{l}_3+100$ mL of 0.1M NaOH

2. 50 mL of 0.1 M $FeC{l}_3+200$ mL of 0.1M NaOH

3. 10 mL of 0.1 M $FeC{l}_3+50$ mL of 0.1M NaOH

4. 200 mL of 0.1 M $FeC{l}_3+800$ mL of 0.1M NaOH

Q.

50 ml of 1M oxalic acid is shaken with 0.5 g of wood charcoal. The final concentration of the solution after adsorption is 0.5 M. Calculate the amount of oxalic acid adsorbed per gram charcoal.

1. 1.575 g

2. 0.05 g

3. 3.15 g

4. None

Q. Which one of the following characteristics is associated with adsorption?

1. $\Delta G,\Delta H\text{and}\Delta S$ all are negative.
2. $\Delta G\text{and}\Delta S$ are negative but $\Delta H$ is positive.
3. $\Delta G$ is negative but $\Delta H\text{and}\Delta S$ are positive.
4. $\Delta G\text{and}\Delta H$ are negative but $\Delta S$ is positive.

Q.

On addition of 0.5 mL of solution of 10% NaCl to 20 mL of red gold sol in presence of 0.025 g of starch, the coagulation is just prevented. The gold number of starch is

1. 0.025

2. 0.1

3. 2.5

4. 1

Q.

50 ml of 1M oxalic acid is shaken with 0.5 g of wood charcoal. The final concentration of the solution after adsorption is 0.5 M. Calculate the amount of oxalic acid adsorbed per gram charcoal.

1. 1.575 g

2. 0.05 g

3. 3.15 g

4. None

Q.

Which one of the following is not a surfactant

1. 

2. 

3. 

4. 

Q. On adding FeCl₃ solution into NaOH solution, a possitively charged colloidal sol is obtained when the following are mixed:

1. 100 mL of 0.1 M FeCl₃ + 100 mL of 0.1M NaOH

2. 50 mL of 0.1 M FeCl₃ + 200 mL of 0.1M NaOH

3. 10 mL of 0.1 M FeCl₃ + 50 mL of 0.1M NaOH

4. 200 mL of 0.1 M FeCl₃ + 800 mL of 0.1M NaOH

Q.

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

1. 

2. 
   

3. 
   

4. 

Q.

Ferric hydroxide sol is positively charged colloid. The coagulating power of

ions would be in the order

1. 
2. 
3. 
4. 

Q.

Which one is not a colloidal solution

1. Air

2. Smoke

3. Blood

4. Ink

Q.

Which impurities are removed by the following reagents:

(c) Potassium hydroxide solution

Q.

Freundlich isotherm will be better for modeling

1. Physical adsorption

2. Chemical adsorption

3. Adsorption of liq on solid

4. None

Q.

Which of the following can be a possible contact angle with water for a colloidal particle?

1. $0^{\circ }$

2. ${30}^{\circ }$

3. ${60}^{\circ }$

4. ${100}^{\circ }$

Q.

Which is not colloidal [CPMT 1984; MP PET 1989, 91]

1. Chlorophyll

2. Egg

3. Ruby glass

4. Milk

Q.

Purple of Cassius is

1. Colloidal solution of gold

2. Colloidal solution of Sulphur

3. Colloidal solution of platinum

4. Oxyacids of gold

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. 10
2. 1
3. 0.1
4. 0.01

Q.

Gold number of haemoglobin is 0.03. Hence 100 ml of gold sol will require haemoglobin in what quantity so that gold is not coagulated by 10ml 10% NaCl solution

1. 0.03 mg

2. 0.003 mg

3. 0.3 mg

4. 300 mg

Q.

On addition of 0.8 mL of solution of 10% NaCl to 30 mL of red gold sol in presence of 0.03 g of starch, the coagulation is just prevented. The gold number of starch is

1. 0.09

2. 0.4

3. 0.0375

4. 5