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

Among the given options, which element is the minimum required for precipitation of a negatively charged suspension of clay in water?

1. Aluminium chloride.

2. Potassium sulphate.

3. Sodium hydroxide.

4. Hydrochloric acid.

What is a colloidal solution that is commonly used to treat skin diseases?

1. Colloidal sulphur.                   

2. Colloidal silver.

3. Colloidal gold.                         

4. Colloidal antimony.

How is the flocculation value expressed?

1. Millimole per litre.

2. Mole per litre.

3. Gram per litre.

4. Mole per millilitre.

KClO₃ on heating decomposes into KCl and O₂. If some MnO₂ is added, the reaction goes much faster because:

1. MnO₂ decomposes to give oxygen.

2. MnO₂ provides  heat by reacting.

3. Better contact is provided by MnO₂

4. MnO₂ acts as a catalyst.

What does blood contain?

1. Positively charged particles.

2. Negatively charged particles.

3. Neutral particles.

4. Negatively as well as positively charged particles.

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.

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.

Brownian movement is caused by:

1. Colloidal solution.

2. True solution.

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

4. All of the above.

The surface tension of lyophilic sols is:

1. Lower than H₂O

2. More than H₂O

3. Equal to H₂O

4. None of the above.