Ncert Exercises & Solutions

Match the items of Column I and Column II.

Column I		Column II
A	Lechlanche cell	1.	Cell reaction 2H₂ +O₂ —> 2H₂O
B	Ni-Cd cell	2.	Does not involve any ion in solution and is used in hearing aids.
C	Fuel cell	3.	Rechargeable
D	Mercury cell	4.	-Reaction at anode, Zn → Zn²⁺ + 2e^-

Codes:

Hint: Lechlanche cell is also known as dry cell

A. Lechlanche cell The electrode reaction occurs at Lechlanche cell are

At anode Zn —> Zn²⁺ + 2e^-
At cathode MnO₄ + NH₄⁺ +e^- —> MnO(OH)+ NH₃

B. Ni-Cd cell is rechargeabie. So, it has more life time.

C. Fuel cell produces energy due to combustion. So, a fuel cell converts the energy of combustion into electrical energy e.g.,

2H₂ +O₂ —> 2H₂O

D. Mercury cell does not involve anion in solution and is used in hearing aids.