In a car battery, electrolyte substance used is

Correct answer: (b) Sulphuric acid

Explanation

A car battery is a lead–acid storage cell (a secondary cell). Its electrolyte is dilute sulphuric acid, with plates of lead dioxide (PbO₂) and spongy lead (Pb).

On discharge both plates turn into lead sulphate; charging reverses this, so the battery can be recharged many times.