Question

In the lead storage battery, what are the charges on the lead species that are reactants or products in reactions that take place at the anode and cathode?
A) 2+ and 4+
B) 0 and 2+
C) 0 and 4+
D) 0, 2+ and 4+
E) 0, 2+ 3+ and 4+

Answer 1

Answer:

D) 0, 2+ and 4+

Explanation:

Lead storage battery consists of metallic lead and lead(IV)oxide in a bath of sulphuric acid.

The negative plate (Cathode) consists of metallic lead in the battery while the positive plate (Anode) consists of Lead(IV)Oxide (PbO2). The liquid in which these plates are suspended in is an aqueous medium of Sulphuric acid (H2SO4).

Negative plate reaction: Pb(s) + HSO4–(aq) → PbSO4(s) + H+(aq) + 2e–

Positive plate reaction: PbO2(s) + HSO4–(aq) + 3H+(aq) + 2e– → PbSO4(s) + 2H2O(l)

Combining these two reactions, one can determine the overall reaction:

Pb(s) + PbO2(s) + 2H+(aq) + 2HSO4–(aq) → 2PbSO4(s) + 2H2O(l)

Pb is in 0 valent state. PbO2 has Pb with 4+ valency. PbSO4 has Pb with 2+ valency.