Question

The reaction of toluene with $C{l}_2$ in the presence of $FeC{l}_3$ gives '$X$' and reaction in presence of light gives '$Y$' Thus, '$X$' and '$Y$' are

• A. X = benzal chloride, Y = o-chlorotoluene
• B. X = m-chlorotoluene, Y = p-chlorotoluene
• C. X = o and p-chlorotoluene, Y = trichloromethyl benzene
• D. X = benzyl chloride, Y = m-chlorotoluene

Answer 1

Answer: (C)

In presence of $FeC{l}_3$ and in dark, electrophilic substitution on the benzene ring by $C{l}^{+}$ion at ortho and para positions occurs to give o- and p- chlorotoluene.
Since methyl group activates the ring at ortho and para positions more than meta positions, the electroscopic substitution occurs mostly at these positions.
$C_6{H}_5-C{H}_3+C{l}_2\stackrel{FeC{l}_3}{\to }\{o$-chlorotoluene $\underset{(X)}{+p}$-chlorotoluene $\}$
Hence, $X$ is o- and p- chlorotoluene.
On the other hand, if chlorine reacts with toluene in the absence of a catalyst but in the presence of UV light, substitution happens in the methyl group rather than the ring.
$C_6{H}_5-C{H}_3+C{l}_2\stackrel{\text{ UV light }}{\to }\underset{(Y)}{C_6{H}_5-CC{l}_3}$
Hence, $Y$ is trichloromethylbenzene.