A metal that forms soluble trioxosulphate (IV) ion is

The soluble trioxosulphate (IV) ion is also known as the sulphate (IV) ion or the sulphite ion, SO32-. This ion is formed when sulphur dioxide gas (SO2) dissolves in water, and reacts with oxygen in the air. Out of the given metals, only one metal can form a soluble trioxosulphate (IV) ion, and that is potassium. Potassium sulphite (K2SO3) is a soluble salt that can dissociate into potassium ions (K+) and sulphite ions (SO32-) in water. Barium can form a sulphite ion, but it is not soluble in water. Manganese can form a sulphate ion, but not a sulphite ion. Aluminium can also form a sulphate ion, but it cannot form a sulphite ion. Therefore, the metal that forms a soluble trioxosulphate (IV) ion is potassium.