Sulphate and sulphite 有咩分別？

Sulphate ion means SO42- ion, and a sulphate means a compound that contains SO42- ion.

Sulphite ion means SO32- ion, and a sulphite means a compound that contains SO32- ion.

Although both sulphate ion and sulphite ion contain sulphur, they have different chemical and physical properties because they have different compositions.
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The most important difference is one has 3 oxygens the other has 4 oxygens. The sulphate is a salt but the sulphite is a reducing agent having the tendercy to obtain another oxygen to be in a more stable state i.e. sulphate.