Question

When a lead storage battery is discharged, then the H+ ion
concentration and amount of PbSO4 (respectively)

Increases, increases

Decreases, increases

Remains same

Increases, decreases
​

Answer 1

Explanation:

Reaction for discharge of lead storage cell is,

Pb+SO

4

2−

→PbSO

4

+2e

−

PbO

2

+4H

+

+SO

4

2−

+2e

−

→PbSO

4

+2H

2

O.

The acid reacts with the positive electrode to to release electrons. In this process the H

2

SO

4

is consumed and residual water is left behind(or evaporated). So, density of sulphuric acid decreases.

Answer 2

When a lead storage battery is discharged, then the H⁺ ion  concentration and amount of PbSO₄ (respectively) :

Decreases, increases

- The chemical reaction of discharging of a lead storage battery is:

Anode: Pb(s) + SO₄²⁻(aq) → PbSO₄ (s) + 2e⁻

Cathode: PbO₂ (s) + SO₄²⁻(aq) + 4H⁺ (aq) + 2e⁻ → PbSO₄ (s) + 2H₂O (l)

- From the above reaction, it is evident that H⁺ ion concentration is decreasing.

- Also, PbSO₄ is forming during the discharging of the battery.

- So, the correct answer is that the H⁺ ion  concentration and amount of PbSO₄ are decreasing and increasing respectively.