Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

Surface Chemistry

Short Answer Type

201. How does chemical adsorption of a gas on a solid vary with temperature?

215 Views

202. How does the addition of alum purify water?

902 Views

203. State one difference between an emulsion and a sol.

316 Views

204. Give an example of heterogeneously catalysed reaction.

138 Views

205.
(a) How can a colloidal solution and true solution of the same colour be distinguished from each other ?
(b) List four applications of adsorption.

Answer:

a) True solution posses molecular dimensin 10^-10 to 10^-9m. Whereas in colloidal solution the sizes of particles is 1-100nm thus colloidal solution show tyndall effect. thus we can distinguised true solution and colloidal solution by tyndall effect.

b)

(i) Production of high vacuum: The remaining traces of air can be adsorbed by charcoal from a vessel evacuated by a vacuum pump to give a very high vacuum.

(ii) Gas masks: Gas mask (a device which consists of activated charcoal or mixture of adsorbents) is usually used for breathing in coal
mines to adsorb poisonous gases.

(iii) Control of humidity: Silica and aluminium gels are used as adsorbents for removing moisture and controlling humidity.

(iv) Removal of colouring matter from solutions: Animal charcoal removes colours of solutions by adsorbing coloured impurities.

434 Views

206.

Explain the following observations:
(a) Lyophilic colloids are more stable than lyophobic colloid.
(b) Coagulation takes place when sodium chloride solution is added to a colloidal solution of ferric hydroxide.
(c) Sky appears blue in colour.

1110 Views

207.

(a) In which of the following does adsorption take place and why?
(i) Silica gel placed in the atmosphere saturated with water.
(ii) Anhydrous CaCl₂ placed in the atmosphere saturated with water.
(b) How does BF₃ act as a catalyst in industrial process?
(c) Give an example of shape selective catalysis.

1669 Views

208. What are micelles? How do they differ from ordinary colloidal particles ? Give two examples of micelles forming substances.

862 Views

209. State Hardy-Schulze rule.

336 Views

Long Answer Type

210.

(a) Of NH₃ and CO₂ which will be adsorbed more readily on the surface of charcoal and why?
(b) How are multimolecular colloids different from macro-molecular colloids?
(c) State the principle of electro-dialysis.

1729 Views