Question

The electrolyte used in lead storage battery is

• A. 10% $H_{2}SO_{4}$ aqueous solution
• B. 60% $H_{2}SO_{4}$ solution
• C. 38% $H_{2}SO_{4}$ aqueous solution
• D. 38% HCl aqueous solution
• E. 60% HCl aqueous solution

Hint:

The density of the 38% $H_{2}SO_{4}$ solution is about 1.30 g/mL when fully charged.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
This is a factual question about the composition of a lead-acid battery, a common type of rechargeable battery used in vehicles.
Step 2: Detailed Explanation:
A lead-acid battery consists of: - Anode (Negative Electrode): Spongy lead (Pb). - Cathode (Positive Electrode): Lead dioxide (PbO\(_2\)). - Electrolyte: An aqueous solution of sulfuric acid (H\(_2\)SO\(_4\)). The concentration of the sulfuric acid is crucial for the battery's performance. In a fully charged battery, the electrolyte is typically a solution of about 35-40% sulfuric acid by weight, which corresponds to a density of about 1.28 g/cm\(^3\). The value of 38% is a standard, commonly cited concentration. During discharge, both electrodes are converted to lead sulfate (PbSO\(_4\)), and the sulfuric acid is consumed, turning into water. This decreases the concentration and density of the electrolyte, which is why a hydrometer can be used to check the state of charge of the battery. - Options (D) and (E) are incorrect because the electrolyte is sulfuric acid, not hydrochloric acid. - Options (A) and (B) represent incorrect concentrations. 10% is too dilute, and 60% is too concentrated for a typical battery. Step 3: Final Answer:
The electrolyte used in a lead storage battery is a 38% H\(_2\)SO\(_4\) aqueous solution.