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CBSE Chemistry Class 12 Sample Paper – SURFACE CHEMISTRY

MM : 25                                     TIME : 40 MIN.
1. Name the catalyst used in the Ostwald process for the manufacture of nitric acid .
2. What happens when a colloidal sol of Fe(OH)3 is mixed with that of As2S3 ?
3. How does alum helps in the purification of water with suspended impurities ?
4. Define gold number .
5. Why sky appears blue in the colour ?
6. Write down the difference between sols and emulsions.
7. What does activity and selectivity of catalyst means ? Explain.
8. What is CMC and Kraft temperature with respect to Micelles formation?
9. What is the difference between adsorption isotherm and adsorption isobar ?
10.In which of the following does adsorption takes place
(i) Silica gel placed in the atmosphere containing water .
(ii) Anhydrous CaCl2 placed in the atmosphere containing water .
11.Differentiate between multimolecular, macromolecular and associated colloids ?
12.Write short note on (a) Electrophoresis (b) Peptization .
13.Differentiate between (a) Physical and chemical adsorption (b) Lyophillic and Lyophobic colloids .

 

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