CBSE Class 12 Chemistry Worksheet - Surface Chemistry. CBSE issues sample papers every year for students for class 12 board exams. Students should solve the CBSE issued sample papers to understand the pattern of the question paper which will come in class 12 board exams this year. The sample papers have been provided with marking scheme. It’s always recommended to practice as many CBSE sample papers as possible before the board examinations. Sample papers should be always practiced in examination condition at home or school and the student should show the answers to teachers for checking or compare with the answers provided. Students can download the sample papers in pdf format free and score better marks in examinations. Refer to other links too for latest sample papers.
Q1. Anhydrous CaCl2 is put in a vessel containing water vapours. Name the phenomena that will occur.
Q2. Why is absorption always exothermic? Justify on basis of thermodynamic criteria.
Q3. In an absorption process 20 kJ mol-1 heat is liberated. What type of absorption will this be? Give any two characteristics of this absorption.
Q4. Give reasons for the following:-
(a) Sky appears blue in colour.
(b) Gelatin is generally added to ice creams.
(c) Silica gel is used as a dehumidizer.
(d) If ferric chloride is added to water, -ve sol is formed whereas addition of FeCl3 to sodium hydroxide solution gives +sol.
(e) Colloidal sol of Ag I prepared by mixing KI & AgNo3 can bear +ve or -ve charge depending upon stoichlometry of solutions.
(f) Bleeding from a cut can be stopped by rubbing alums.
(g) Rubber can be obtained by adding acetic and to latex.
(h) Alums are used to purify muddy water.
(i) Deltas are formed when river water meets sea water.
(j) Most of the medicines used are in the colloidal form.
Q5. NaCl added to an emulsion enhances its conductivity. What type of emulsion will this be?
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