Test: Electrochemical Cells


10 Questions MCQ Test Chemistry Class 12 | Test: Electrochemical Cells


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This mock test of Test: Electrochemical Cells for Class 12 helps you for every Class 12 entrance exam. This contains 10 Multiple Choice Questions for Class 12 Test: Electrochemical Cells (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Electrochemical Cells quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Electrochemical Cells exercise for a better result in the exam. You can find other Test: Electrochemical Cells extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
QUESTION: 1

Salt bridge is indicated in the cell representation by :

Solution:
QUESTION: 2

If a salt bridge is removed between the half cells, the voltage

Solution:

The correct answer is Option A.

The purpose of a salt bridge is not to move electrons from the electrolyte, rather maintain charge balance because the electrons are moving from one-half cell to the other. The electrons flow from the anode to the cathode thus if a salt bridge is removed between the half cells, the voltage becomes zero.
 

QUESTION: 3

The cell representation of the given reactions is:
Zn(s) + 2Ag+ → Zn2+ + 2Ag(s)

Solution:

The correct answer is Option D
For the cell reaction
Zn(s) + 2Ag+(aq) → 2Ag(s) + Zn2+(aq) 
The two half cell reactions are
Zn(s) → Zn2+(aq) + 2e
Ag+(aq) + e− → Ag(s) × 2
Zn(s) + 2Ag(aq) → Zn2+ + 2Ag(s)
Therefore Zn is oxidised and as such acts as -ve electrode or anode. Ag+Ag+ ions get reduced as such the Ag electrode acts as a cathode or _ve electrode. Therefore cell representation is
Zn∣∣Zn2+∣∣∣Ag+∣∣Ag

QUESTION: 4

 In an electrochemical cell, the electrode having a higher reduction potential will act as:

Solution:

The correct answer is option D.

Reduction potential refers to the voltage required to reduce a material under standard conditions. If a material has a higher reduction potential it takes more energy to reduce it than a lower reduction potential material. Therefore the higher reduction potential material is actually oxidized to reduce the lower reduction potential material.
Cathode- The electrode where reduction occurs and
The one with the highest reduction potential selected as the reduction half-reaction and therefore is cathode.

QUESTION: 5

The cell representation of the given reaction is:
Zn(s) + Cu2+ → Zn2+ + Cu(s)

Solution:

The correct answer is Option A
Zn + Cu++ → Zn++ + Cu
At cathode: Cu++ + 2e → Cu
At anode: Zn − 2e → Zn
∴ Cell representation
Zn∣Zn++∣∣Cu++∣Cu

QUESTION: 6

 In a Daniel cell, the oxidation and reduction halves occur at:

Solution:
QUESTION: 7

During electrolysis, the reaction that takes place at cathode is:

Solution:

The reaction at the anode is oxidation and that at the cathode is reduction. Here, the anode is positive and cathode is the negative electrode. The reaction at the anode is oxidation and that at the cathode is reduction.

QUESTION: 8

. In the construction of a salt bridge, saturated solution of KNO3 is used because:

Solution:

The correct answer is Option A.

For a good salt bridge, the velocities of ions should be the same. If the velocities are not the same, then the ions would not be able to neutralize the charge equally in both half cells. Consequently, an opposite force would be developed that restricts the flow of current. For KNO3, the velocities of K+and NO3- are nearly the same. Therefore, it is used to make salt bridges

QUESTION: 9

 During electrolysis, the reaction that takes place at anode is:

Solution:

The correct answer is Option D
oxidation
The reaction at the anode is oxidation and that at the cathode is reduction. The electrons are supplied by the species getting oxidized. They move from anode to the cathode in the external circuit.

QUESTION: 10

 In an electrochemical cell, the electrode having a lower reduction potential will act as:

Solution:

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