A. Phosphoric acid
B. hydrochloric
C. trioxonitrate (V)
D. tetraoxosulphate (VI)
Correct Answer:
Option A – Phosphoric acid
Explanation:
Some acids remove rust (oxides), while others cause rust. Most acids will etch metal whether they cause rust or remove it. Phosphoric acid (H3PO4) is one type of acid which removes rust by converting it (iron III oxide) to a form that can be dissolved in water. Most other strong acids cause rust. Please note that some rust removers contain hydrofluoric acid (HF), which is extremely dangerous, since it penetrates your skin, destroys bone, and can cause heart attack, without you even feeling its presence. If you’re using any kind of rust remover, read the label carefully and always wear goggles, chemical-resistant gloves, and protective clothing.
