Cloud bursts are caused by?

1.	Attraction towards the electrical charges on the earth.
2.	Large amount of water present in the cloud.
3.	Dense clouds are present in the upper atmosphere.
4.	Mutual discharge of oppositely charged clouds resulting in the coagulation.

Peptization is the process of?

1. Precipitating colloidal particles.

2. Purifying colloidal particles.

3. Dispersing the precipitate into a colloidal state.

4. None of the above.

Which is the electrolyte that is least effective in causing coagulation of +ve ferric hydroxide sol?

1. KBr

2. K₂SO₄

3. K₂CrO₄

4. K₃[Fe(CN)₆]

In adding 1 mL of solution of 10 % NaCl to 10 mL of gold solution in the presence of 0.25 g of starch, the coagulation is just prevented. Starch has a gold number equal to:

1. 0.25                     

2. 2.5

3. 250                     

4. 0.025

What is a solution that isn't a lyophilic colloid?

1. Milk

2. Gum

3. Fog

4. Blood

The surface tension of lyophilic sols is:

1. Lower than H₂O

2. More than H₂O

3. Equal to H₂O

4. None of the above.

Brownian movement is caused by:

1. Colloidal solution.

2. True solution.

3. Suspension having size <1000 m$\mathrm{\mu }$.

4. All of the above.

What does the name "aquadag" refer to?

1. Cu in water sol.

2. Pt in water sol.

3. Graphite in water sol.

4. None of the above.

What results are obtained from adding FeCl₃ to K₄[Fe(CN)₆] in a diluted, cold solution?

1. Prussian blue sol.                     

2. Fe₄[Fe(CN)₆]₃ sol.

3. Positive sol.                               

4. All of the above.

Which of the following electrolytes, Na₂SO₄, CaCl₂, Al₂(SO₄)₃, and NH₄Cl, is the most effective coagulating agent for Sb₂S₃ sol?

1. Na₂SO₄                             

2. CaCl₂

3. Al₂(SO₄)₃                           

4. NH₄Cl