Question

In lead storage battery, what happens to the mass of PbO2
on charging and discharging respectively?

Increases, decreases
Decreases, increases
Increases, increases
Decreases, decreases​

Answer 1

Answer:

Explanation:

3rd option

Answer 2

In a lead storage battery, on charging and discharging, the mass of PbO₂ respectively:

(a) Increases, Decreases

• The cathode of a lead storage battery is made up of a grid of lead packed with PbO₂.
• During discharging, this PbO₂ is converted into PbSO₄.
• PbO₂ + SO₄²⁻ + 4 H⁺ + 2 e⁻ ⇄ PbSO₄ + 2 H₂O

• So the mass of PbO₂ decreases during discharging.
• During charging, the reverse process takes place and PbSO₄ is converted into PbO₂.
• PbSO₄ + 2 H₂O ⇄ PbO₂ + SO₄²⁻ + 4 H⁺ + 2 e⁻

• So, its mass increase on charging.