A benzene derivative did not produce white precipitate with the ammonical silver nitrate solution but decolorised the cold dilute alkaline $\mathrm{KMnO}_4$ solution. The compound is

• A

  $\mathrm{C}_8 \mathrm{H}_6$
• B

  $\mathrm{C}_8 \mathrm{H}_{10}$
• Correct answer
  C

  $\mathrm{C}_8 \mathrm{H}_8$
• D

  $\mathrm{C}_7 \mathrm{H}_8$

Solution

$\mathrm{C}_8 \mathrm{H}_8$ is
It is a derivative of benzene and decolorised the cold alkaline $\mathrm{KMnO}_4$ solution. The reaction occurs as follows : $\mathrm{C}_8 \mathrm{H}_8+2 \mathrm{KMnO}_4 \longrightarrow \mathrm{KC}_8 \mathrm{H}_5 \mathrm{O}_2$ $+2 \mathrm{MnO}_2+\mathrm{KOH}+\mathrm{H}_2 \mathrm{O}$

Hence, the correct answer is option: 'C'.