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Home Questions TQSQ4DAZ3U
Target Exam

CUET

Subject

Chemistry

Chapter

Physical: Electro Chemistry

Question:

Match the entries of column I with appropriate entries of column II and choose the correct option out of the four options given.

Column I Column II
(i) Leclanche cell (a) cell reaction 2H2 + O2 → 2H2O
(ii) Ni-Cd cell (b) does not involve any ion in solution and is used in hearing aids
(iii) Fuel cell (c) rechargeable
(iv) Mercury cell (d) reaction at anode, Zn → Zn2+ + 2e-
Options:

(i)-(c), (ii)-(d), (iii)-(a), (iv)-(b)

(i)-(d), (ii)-(c), (iii)-(a), (iv)-(b)

(i)-(a), (ii)-(d), (iii)-(c), (iv)-(b)

(i)-(b), (ii)-(a), (iii)-(c), (iv)-(d)

Correct Answer:

(i)-(d), (ii)-(c), (iii)-(a), (iv)-(b)

Explanation:

(i) Leclanche cell: It is a form of dry cell. The reactions taking place at the electrodes are quite complex. However, they can be represented by:

At anode: Zn(s) → Zn2+(aq) + 2e-

At cathode: 2MnO2(s) + 2NH4+(aq) + 2e- → Mn2O3(s) + 2NH3(g) + H2O

(ii) Ni-Cd cell: This is rechargeable cell which is becoming more and more popular especially in the calculators.

(iii) Fuel cell: It convert energy produced during combustion of fuels directly into electrical energy.

The following electrode reactions take place:

At anode: 2H2(g) + 4OH-(aq) → 4H2O(l) + 4e-

At cathode: O2(g) + 2H2O(l) + 4e- → 4OH-(aq)

Overall reaction: 2H2(g) + O2(g) → 2H2O(l)

(iv) Mercury cell: This is a newer type of dry cell which has found use in low current devices such as hearing aids and watches.

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