Surface Chemistry

Assertion : Lyophilic colloid protects lyophobic colloid. Reason : Lyophilic colloid particles cover up the particles of the lyophobic colloid.

Which of the following statements is incorrect about colloidal solution?

Assertion : Soap is mixed to form O/W emulsion. Reason : Soap reduces surface tension.

Assertion : On passing electric current in colloidal solution they do not move towards anode or cathode. Reason : They do not contain any charge.

Assertion : $\mathrm{Fe}(\mathrm{OH})_3$ and $\mathrm{As}_2 \mathrm{~S}_3$ colloidal sols on mixing precipitate. Reason : $\mathrm{Fe}(\mathrm{OH})_3$ and $\mathrm{As}_2 \mathrm{~S}_3$ combine and form precipitate of…

Assertion : Activity of an enzyme is $\mathrm{pH}$-dependent. Reason : Change in $\mathrm{pH}$ affects the solubility of the enzyme in water.

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

Paints and hair creams are respectively

Assertion: $\mathrm{Fe}^{3+}$ can be used for coagulation of $\mathrm{As}_2 \mathrm{~S}_3$ sol. Reason: $\mathrm{Fe}^{3+}$ reacts with $\mathrm{As}_2 \mathrm{~S}_3$ to give $\mathrm{Fe}_2 \mathrm{~S}_3$.

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

Assertion : Coagulation power of $\mathrm{Al}^{3+}$ is more than $\mathrm{Na}^{+}$. Reason: Greater the valency of the flocculating ion added, greater is its power to cause precipitation (Hardy-Schulze rule).

Which one of the following is an example for homogeneous catalysis?