🔍 Key Concepts

• Lead-acid battery chemistry and what happens at the plates and in the electrolyte during charging • The gas produced when water in the electrolyte breaks down during charging • Typical safety hazards in a battery charging room on ships

💭 Think About

• Think about what part of the battery (acid, lead, or water) is most affected when current is applied to recharge it. • Consider what by‑products are formed when you overcharge or charge a lead‑acid battery for a long time. • Ask yourself which listed hazard is truly unavoidable whenever a lead‑acid battery is charged, even under normal, safe conditions.

✅ Before You Answer

• Remember that sulfuric acid is already inside the battery – does normal charging automatically mean acid must escape? • Recall whether lead stays solid on the plates or becomes a vapor or mist during normal charging. • Think about which option involves a gas that can accumulate in poorly ventilated spaces and is a known explosion risk near open flames or sparks.