Explain the oxidising and reducing property of `SO_(2)`.

Explanation

Oxidising property : Sulphur dioxide, oxidises hydrogen sulphide to sulphur and magnesium to magnesium oxide.
`2H_(2)S+SO_(2) rarr 3S+2H_(2)O`
`2Mg+SO_(2)rarr 2MgO+S`
Reducing property : As it can readily be oxidised, it acts as a reducing agent. It reduces chlorine into hydrochloric acid.
`SO_(2)+2H_(2)O+Cl_(2) rarr H_(2)SO_(4)+2HCl`
It also reduces potassium permanganate and dichromate to `Mn^(2+)` and `Cr^(3+)` respectively.
`2KMnO_(4)+5SO_(2)+2H_(2)O rarr K_(2)SO_(4)+2MnSO_(4)+2H_(2)SO_(4)`
`K_(2)Cr_(2)O_(7)+3SO_(2)+H_(2)SO_(4)rarr K_(2)SO_(4)+Cr_(2)(SO_(4))_(3)+H_(2)O`