Question

Which of the following hydrocarbons can decolorize the alkaline potassium permanganate solution?

• A. $C_2{H}_6$
• B. $C_3{H}_8$
• C. $C_5{H}_{12}$
• D. $C_3{H}_6$

Answer 1

Answer: (D)

$C_3{H}_6$

$C_3{H}_6$ Propene readily reacts with alkaline $KMn{O}_4$ to form propenol. One hydroxyl group attaches to each carbon on either side of the carbon - carbon double bond. $KMn{O}_4$ is first reduced to $Mn{O}_4^{-}2$, a dark green solution and is then furthur reduced to $Mn{O}_2$, a dark brown precipitate, which is further reduced to $M{n}^{+}2$ions.

Alkanes are saturated hydrocarbons, as they are bonded by Hydrogen atoms, and are fully stable, participate in few reactions.