Surface Chemistry

This is a Multiple Choice Type Questions as classified in NCERT Exemplar

Ans: (i) and (iii)

Freundlich gave an empirical relationship between the quantity of gas adsorbed by unit mass of solid adsorbed and pressure at a particular temperature.

$\frac{\mathrm{x}}{\mathrm{p}}$ =kp $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$\mathrm{n}$}\right.$

If $\frac{1}{\mathrm{n}}$  = 0 ; $\frac{\mathrm{x}}{\mathrm{m}}$  = k xtent of adsorption is independent of pressure

When n=0 ; $\frac{\mathrm{x}}{\mathrm{m}}$  = kp

$\frac{\mathrm{x}}{\mathrm{m}}$  vs p is a line

parallel to x-axis

This is a Multiple Choice Type Questions as classified in NCERT Exemplar

Ans: (i) and (ii)

The action of a catalyst is selective in nature and so a substance which acts as a catalyst in one reaction may fail to catalyse another reaction. They also do not change the enthalpy of reaction hence the answer is (i) and (ii).

This is a Multiple Choice Type Questions as classified in NCERT Exemplar

Ans: (ii) and (iii)

The formation of micelles takes place only above a particular temperature which is the Kraft temperature (Tk ) and above a particular concentration i.e., the critical micelle concentration (CMC). Upon dilution, these colloids revert back to the individual ions hence the answer is (ii) and (iii).

This is a Multiple Choice Type Questions as classified in NCERT Exemplar

Ans: Correct option is (ii)

In the figure adsorption of coloured particle from charcoal is shown. Solution of raw sugar is filtered by animal charcoal

and yellowish brown colour of raw sugar is adsorbed and filterate is colourless which gives white colour on crystallization

hence the answer is (ii).

This is a Multiple Choice Type Questions as classified in NCERT Exemplar

Ans: Correct answer is (iv)

Charge on the sol particles can be a result of the following:

Due to electron capture by sol particles during electrodispersion of metals,

Due to preferential adsorption of ions from solution and/or

Due to formulation of electrical double layer.

Hence the correct answer is (iv)

This is a Multiple Choice Type Questions as classified in NCERT Exemplar

Ans: Correct option is iii.

River water is a colloidal solution of clay. Sea water contains a number of electrolytes. When river water meets the sea water, the electrolytes present in sea water coagulate the colloidal solution of clay resulting in its deposition with the formation of delta hence the answeris (iii).

This is a Multiple Choice Type Questions as classified in NCERT Exemplar

Ans: Correct answer is (ii)

The correct sequence of steps involved in catalysis are:

(i) Adsorption of A and B on surface

(ii) Interaction between A and B to form intermediate

(iii) Starting of desorption from surface

(iv) Complete desorption from the surface

Therefore, the correct answer is (ii)

This is a Multiple Choice Type Questions as classified in NCERT Exemplar

Ans: Correct option is (iv).

Colloidal particles are bigger aggregate than the number of particles in a colloidal solution hence, the values of

colligative are of small order as compared to values shown by true solutions at same concentration so the answer is (iv).