Q.What happens when ethylene is passed through cold dilute alkaline Potassium Permanganate ?

Cold, dilute, alkaline potassium permanganate (Baeyer's reagent) is a mild oxidising agent that adds two -OH groups across a carbon-carbon double bond. …

The question asks what happens when ethylene (ethene) is treated with cold dilute alkaline KMnO4 (Baeyer's reagent).

Cold, dilute, alkaline potassium permanganate solution is known as Baeyer's reagent. It is a mild oxidising agent that carries out syn-hydroxylation of a carbon-carbon double bond, adding one -OH group to each of the two doubly-bonded carbons (a 1,2-diol is formed).

When ethylene is passed through it:

CH2=CH2 + H2O + [O] → HO-CH2-CH2-OH (ethane-1,2-diol / ethylene glycol)

The balanced equation is:

3 CH2=CH2 + 2 KMnO4 + 4 H2O → 3 HOCH2-CH2OH + 2 MnO2 + 2 KOH …