Write a test to detect the presence of double bond in a molecule.

Explanation

Detection of double bond: (i) When `Br_(2)` in `C Cl_(4)` is added to the solution of an unsaturated compounds in `C Cl_(4)`, the orange colour of `Br_(2)` disappears due to the formation of a colorless dibromo derivative.

(ii) Baeyer's test : When a cold dilute alkaline solution of `KMnO_(4)` is added to the aqueous solution or suspension of an unsaturated compound, the pink colour of `Km=MnO_(4)` solution is discharged due to the formation of the corresponding 1,2-diol.