Question

Rank the following compounds in decreasing order of reactivity in electrophilic aromatic substitution reaction

• A. 3 > 1 > 2 > 4
• B. 4 > 3 > 2 > 1
• C. 3 > 1 > 4 > 2
• D. 1 > 3 > 4 > 2

Answer 1

Answer: (C)

Rate of electrophilic aromatic substitution is effected by group/s already present. If they $\left(-O-,-NH-,-C{H}_2-\right)$ are ring activating and ortho, para directing due to +R and +H effects reactivity is more but if they $\left(-CO-,-N{O}_2,-CN\right)$ are ring deactivating and meta directing groups due to -R and -H effects reactivity decreases.

Here reactivity order is 3 > 1 > 4 > 2.