Surface tension of lyophilic sols is :

 

1. Lower than water.

2. More than water.

3. Equal to water.

4. None of the above.

All colloids:

1. Are suspension of one phase in another.

2. Are two-phase systems.

3. Contain only water-soluble particles.

4. Are true solutions.

The minimum amount of an electrolyte required to cause coagulation of a sol is called :

1. Coagulation value

2. Gold number

3. Protective value

4. None of these

Peptization involves:

1. Precipitation of colloidal particles.

2. Disintegration of colloidal aggregates.

3. Purification of colloids.

4. Both (1) and (3)

An emulsifying agent is a substance which 

1. Stabilizes the emulsion.

2. De-stabilizes the emulsion.

3. Coagulates the emulsion.

4. Break the interfacial film between suspended particle and medium.

Blue colour of the sky is due to :

1. Absorption of light by dust particles.

2. Reflection of light by dust particles.

3. Scattering of light by dust particles.

4. None of the above.

The Brownian movement of colloidal particles is because of –

1. Convection currents in the fluid

2. Unequal bombardments by the molecules of the dispersion medium on colloidal particles

3. Setting of dispersed phase under gravity

4. Thermal gradient in the medium

When ${\mathrm{FeCl}}_3$ solution is added to $\mathrm{NaOH}$ a negatively charged sol is obtained. It is due to the

(1) Presence of basic group

(2) Preferential adsorption of ${\mathrm{OH}}^{–}$ ions

(3) Self dissociation

(4) Electron capture by sol particles 

Graph between log $\frac{\mathrm{x} }{\mathrm{m}}$ and log P is a straight line inclined at an angle $\mathrm{\theta }$- 45°. When pressure of 0.5 atm and log k = 0.699, the amount of solute adsorbed per g of adsorbent will be

(1) 1 g/g adsorbent                             

(2) 1.5 g/g adsorbent

(3) 2.5 g/g adsorbent                           

(4) 0.25 g/g adsorbent

The stabilization of the dispersed phase in a lyophobic sol is due to

(1) The viscosity of the medium

(2) The surface tension of the medium

(3) Liking for the medium

(4) The formation of an electrical layer between the two phases