Question

A metal used in storage batteries is:
A. $Cu$
B. $Pb$
C. $Sn$
D. $Ni$

Answer 1

Hint: Try to recall that storage batteries are those batteries which we use in our homes. Also, they can be charged again by supplying direct current (DC) unlike primary cells which can’t be reused , when they get discharged.

Complete step by step solution:
Storage battery, also known as rechargeable battery, is an electrochemical cell or group of electrochemical cells that converts chemical energy by reversible chemical reactions and they can be recharged again by-passing direct current through it in the direction opposite to that of its discharge.
They are also known as “accumulators” as they can store energy through reversible chemical reaction.
One of the examples of storage batteries is Lead-acid batteries. This is the best-known rechargeable battery in which lead electrode, $Pb\left( s \right)$ is used as anode, lead dioxide, $Pb\mathop O\nolimits_2 \left( s \right)$ is used as cathode and $\mathop H\nolimits_2 S\mathop O\nolimits_4 \left( {aq} \right)$ is used as electrolyte.
The lead storage battery can produce a large initial current, which is an essential feature when starting an automobile engine.
During discharging, when the cell the lead anode is oxidized to lead (II) sulphate, an insoluble substance that adheres to the electrode surface. The two electrons produced per lead atom move through the external circuit to the cathode, where it is reduced to ions in the presence of and form lead (II) sulphate.
The chemical reaction which takes place both anode and cathode of lead-acid battery are as follows-
Anode- $Pb\left( s \right) + \mathop {S\mathop O\nolimits_4 }\nolimits^{2 - } \left( {aq} \right) \to PbS\mathop O\nolimits_4 \left( s \right) + 2\mathop e\nolimits^ - $
Cathode-$Pb\mathop O\nolimits_2 \left( s \right) + 4\mathop H\nolimits^ + \left( {aq} \right) + \mathop {S\mathop O\nolimits_4 }\nolimits^{2 - } \left( {aq} \right) + 2\mathop e\nolimits^ - \to PbS\mathop O\nolimits_4 \left( s \right) + 2\mathop H\nolimits_2 O\left( l \right)$
And, the overall cell reaction is \[Pb\left( s \right) + Pb\mathop O\nolimits_2 \left( s \right) + 2\mathop H\nolimits_2 S\mathop O\nolimits_4 \left( {aq} \right) \to 2PbS\mathop O\nolimits_4 \left( s \right) + 2\mathop H\nolimits_2 O\left( l \right)\]

Therefore, out of all the 4 options given above we can now say that option B is the correct answer.

Note: It should be remembered that lead-acid batteries are capable of being recharged, which is very important for their use in cars.Also, during discharging of lead-acid batteries, electrolyte loses much of its dissolved sulphuric acid.