Case Study Questions for Class 12 Chemistry Chapter 3 Electrochemistry

There is Case Study Questions in class 12 Chemistry in session 2020-21. For the first time, the board has introduced the case study questions in the board exam. The first two questions in the board exam question paper will be based on Case Study and Assertion & Reason. The first question will have 5 MCQs out of which students will have to attempt any 4 questions. The second question will carry 5 Assertion & Reason type questions with the choice to attempt any four. Here are the questions based on case study.

Case Study Question 1:

Read the passage given below and answer the following questions:

All chemical reactions involve interaction of atoms and molecules. A large number of atoms/molecules are present in a few gram of any chemical compound varying with their atomic/molecular masses. To handle such large number conveniently, the mole concept was introduced. All electrochemical cell reactions are also based on mole concept. For example, a 4.0 molar aqueous solution of NaCl is prepared and 500 mL of this solution is electrolysed. This leads to the evolution of chlorine gas at one of the electrode. The amount of products formed can be calculated by using mole concept.

The following questions are multiple choice questions. Choose the most appropriate answer:

(i) The total number of moles of chlorine gas evolved is
(a) 0.5
(b) 1.0
(c) 1.5
(d) 1.9

(ii) If cathode is a Hg electrode, then the maximum weight of amalgam formed from this solution is
(a) 300g
(b) 446 g
(c) 396 g
(d) 256 g

or

The total charge (coulomb) required for complete electrolysis is
(a) 186000
(b) 24125
(c) 48296
(d) 193000

(iii) In the electrolytes, the number of moles of electrons involved are
(a) 2
(b) 1
(c) 3
(d) 4

(iv) In electrolysis of aqueous NaCl solution when Pt electrode is taken, then which gas is liberated at cathode?
(a) H2 gas
(b) Cl2 gas
(c) O2 gas
(d) None of these

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