Aviation Institute of Maintenance (AIM) Block 2 Practice Exam

Neutralizing the Ni-Cd electrolyte is about handling a caustic alkaline solution safely. Ni-Cd batteries use potassium hydroxide as the electrolyte, so spills are highly caustic and can cause severe burns. Boric acid is used because it’s a mild acid that can neutralize the alkali without creating aggressive conditions, turning the caustic solution into relatively safer compounds (potassium borate) and water. This makes the spill easier to manage and reduces corrosion risk. Using a strong base would not neutralize the solution and would just make the alkalinity worse, and the neutralization process itself does not produce hazardous gas.