181.

Gasoline is

• C₁₇H₃₆ to C₂₁H₅₀

• C₇H₂₄ to C₁₄H₃₄

• C₇H₁₆ to C₁₀H₂₂

• C₃H₈ to C₆H₁₄

A emulsifier is a substance which :

• stabilises the emulsion

• homogenises the emulsion

• coagulates the emulsion

• accelerates the dispersion of liquid in liquid

The coagulation of 200 mL of a positive colloid took place when 0.73 g HCl was added to it without changing the volume much. The flocculation value of HCl for the colloid is

• 100

• 36.5

• 0.365

• 150

Paints and hair creams are respectively

• sol and emulsion

• aerosol and foam

• emulsion and sol

• foam and gel.

Extent of adsorption of adsorbate from solution phase increases with :

• increase in amount of adsorbate in solution

• decrease in surface area of adsorbent

• increase irtemperature of solution

• decrease in amount of adsorbate in solution

Which ofthe following is a negatively charged sol ?

• Sol of charcoal

• Haemoglobin

• TiO₂ sol

• Basic dye stuffs

The work of conc. H₂SO₄ in esterification process is as :

• dehydrating agent and catalyst

• dehydrating agent

• hydrolysing agent

• catalyst

Purification of colloids is done by

• dialysis

• peptisation

• electrophoresis

• coagulation.

A colloidal solution is kept in dark and is illuminated by a beam of light then, brightness appears at the right angle of direction of light. This effect is called

• Tyndall effect

• Brownian effect

• Hardy-Schulze effect

• none of the above.

Assertion: Coagulation power of Al³⁺ is more than Na⁺.

Reason:Grealer the valency ofthe flocculating ion added, greater is its power to cause precipitation (Hardy-Schulze rule).

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.