Which statement correctly identifies a neutralizer for nickel-cadmium battery electrolyte spilled on aircraft structures?

• A. Hydrochloric acid.
• B. Sodium hydroxide solution.
• C. Bicarbonate of soda and water.
• D. Boric acid and water, or vinegar.

Answer: (D)

The spill is an alkaline electrolyte (potassium hydroxide) from a nickel-cadmium battery, so the safe way to handle it is to neutralize the base with a mild acid. Boric acid and water, or vinegar (acetic acid), are appropriate choices because they provide gentle, controllable neutralization that converts the caustic base into safe salts and water without generating harsh fumes or highly corrosive residues. This helps protect aircraft skin and components, especially aluminum, and minimizes heat and damage during cleanup.

Hydrochloric acid is a strong acid and can cause rapid, aggressive corrosion and harmful fumes in the aircraft environment. Sodium hydroxide solution would keep the spill caustic rather than neutralize it. Bicarbonate of soda and water is a weak base/ buffering agent and is not the preferred neutralizer for an alkaline spill, as it’s less effective and may leave residues that aren’t ideal for post-cleanup surfaces.