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

Which of the following reactions leads to the formation of a substance in colloidal state?

(A) $2{\mathrm{HNO}}_3+3{\mathrm{H}}_2\mathrm{S}\stackrel{ }{\to }3\mathrm{S}+3{\mathrm{H}}_2\mathrm{O}+2\mathrm{NO}$

(B) ${\mathrm{SnCl}}_2+{\mathrm{HgCl}}_2\stackrel{ }{\to }{\mathrm{SnCl}}_4+\mathrm{Hg}$

(C) $2\mathrm{Mg}+{\mathrm{CO}}_2\stackrel{ }{\to }2\mathrm{MgO}+\mathrm{C}$

(D) $\mathrm{Cu}+{\mathrm{CuCl}}_2\stackrel{ \mathrm{HCl} }{\to }{\mathrm{Cu}}_2{\mathrm{Cl}}_2$

$1$ $\mathrm{mol}$ of $\left[\mathrm{AgI}\right]{\mathrm{I}}^{-}$ can be coagulated by - 

1. 1 mol of Pb(NO₃)₂                          

2. \(\frac{1}{2}\) mol of Pb(NO₃)₂

3. \(\frac{2}{3}\) mol of Pb(NO₃)₂                           

4. None of the above.

The process of converting precipitate into collidal solution on adding an electrolyte is called:

(1) Peptisation                             

(2) Dialysis

(3) Electro-osmosis                     

(4) Eelectrophoresis

Assertion: Physical and chemical adsorption respond differently to a rise in temperature.

Reason: Chemical adsorption requires some activation energy.