Answer : The correct option is, (B) Hydrochloric acid(HCl)
Explanation :
Rust is an iron oxide, which is formed by the reaction of iron with oxygen in the presence of water.
As we know that the rust is an iron oxide (base) which is removed by an acid.
As per given options, the acid used to remove the rust from the metal is hydrochloric acid and not sulfuric acid because sulfuric acid is an oxidizing agent which oxidizes the metal more.
While the other options, ammonia and sodium hydroxide are a base.
Hence, hydrochloric acid is used to remove rust from metal.
