Question

Which of the following does not give a positive test with alkaline solution of potassium permanganate?

• A. $C_{10}{H}_{22}$
• B. $C_6{H}_{12}$
• C. $C_{10}{H}_{18}$
• D. $C_{10}{H}_{20}$

Answer 1

The correct option is A $C_{10}{H}_{22}$

Alkenes and Alkynes react with bromine to form dibromides. When the potassium permanganate is added, styrene and benzene are oxidized. Alkenes are oxidized to diols and alkynes are oxidized to diones. The alkanes in this situation do not react with the potassium permanganate.
$C_{10}{H}_{22}$ is an alkane as it satisfies the general formula $C_n{H}_{2n+2}$, and hence it does not react with $KMn{O}_4$