Common acids. Common acids and acid-containing household products. The bottles contain (from left): lemon juice, kettle descaler, malt vinegar and concentrated sulphuric acid. Lemon juice contains citric acid and vinegar contains acetic (ethanoic) acid. Both these acids impart a bitter taste to the liquids, but are dilute and safe to consume. Commercial descaling solutions contain the strong and corrosive formic (methanoic) and sulphamic acids to remove deposits of limescale from kettles. Concentrated sulphuric acid is also a strong and corrosive acid, and it is extremely dangerous. It is found in car batteries.