Methods to Form Lyophobic Colloids

Q.

Colloidal solution of arsenious sulphide can be prepared by

[AMU 1985]

1. Electrodispersion method

2. Peptization

3. Double decomposition

4. Hydrolysis]

Q. Also known as the electro-dispersion method, the Bredig’s arc method applies a high voltage between two electrodes of a metal (like gold or silver) immersed in a dispersion medium to obtain a colloidal sol of the metal. Which of the following regarding the electrodes?

1. The electrodes are made of different metals
2. The electrodes are made of the same metals
3. The electrodes are kept very far apart
4. The electrodes are kept close to each other and the dispersion medium is cooled by a freezing mixture

Q. Method of formation of solution is given in Column I. Match it with the type of solution given in Column II.
Column I Column II
(i) Sulphur vapours passed through cold water (p) Normal electrolyte solution
(ii) Soap mixed with water above critical micelle concentration (q) Multi molecular colloids
critical micelle concentration
(iii) White of egg whipped with water (r) Associated colloid
(iv) Soap mixed with water below (s) Macro molecular colloids
critical micelle concentration

1. i-q, ii-r, iii-s, iv-p
2. i-p, ii-q, iii-r, iv-s
3. i-q, ii-p, iii-s, iv-r
4. i-r, ii-s, iii-q, iv-p

Q.

Colloidal solution of arsenious sulphide can be prepared by

[AMU 1985]

1. Electrodispersion method

2. Peptization

3. Double decomposition

4. Hydrolysis]

Q. The INCORRECT statements below regarding colloidal solution is

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1. A colloidal solution shows Brownian motion of colloidal particles.
2. A colloidal solution shows colligative properties.
3. The flocculating power of $A{l}^{3+}$ is more than that of $N{a}^{+}$
4. An ordinary filter paper can stop the flow of colloidal particles.

Q. Bredig's arc method involves :

1. Dispersion as well as condensation of metal particles
2. Dispersion of metal
3. Neither dispersion nor condensation
4. Condensation of metal

Q.

The stabilization of a dispered phase in a lyophobic colloid is due to:

1. the adsorption of charged substances on dispersed phase

2. thelarge electro-kinetic potential developed in the colloid

3. the formation of an electrical layer between two phases

4. the viscosity of the medium