Class 12th

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).

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

Ans: Correct option is (iv).

Solid and liquid together forms up sol. In this case, solid is dispersed phase and liquid is the dispersion medium hence the answer is (iv).

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

Ans: Correct option is (ii)

The rate of coagulation will be faster if the value of oppositely charge electrolyte is high hence the answer is (ii).

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

Ans: Correct option is (iv)

Peptisation is the process in which freshly prepared precipitate can be converted into colloidal solution so the answer is (iv).

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

Ans: Correct option is (iii).

Lyophilic colloids have unique property of protecting lyophobic colloids. When a lyophilic sol is added to lyophobic solution, the lyophilic particles form a layer around the lyophobic particles and protect the latter from electrolytes. Lyophilic colloids used for this purpose are called protective colloids hence the answer is (iii).