A lead storage battery consists of a lead anode and a grid of lead packed with lead dioxide as the cathode. The electrolyte taken is 39% H2SO4 by mass having a density of 1.294 g mL-1. The battery holds 3.5 L of the acid. During the discharge of the battery, the density of H2SO4 falls from 1.294 g mL-1 to 1.139 g mL-1 which is 20% by H2SO4 mass.
What is the amount of charge in coulombs used up by the battery?
Answer & explanation
Correct answer: option 1
The correct answer is option 1. 954180.
\(\text{During discharge reaction, 4 moles of }H^+\text{ ions, i.e., 2 moles of }H_2SO_4\text{ require 2F, i.e., 2 × 96500 coulombs}\)
∴ \(\text{9.88786 moles will require =}\)
\(\frac{2\text{ × }96500\text{ × }9.88786}{2}\)
\(\text{= 954178 coulombs}\)