Question

Which one of the following is not present in the nitration mixture?

• A. $\overset{+}NO_2$
• B. $HSO_4^{-}$
• C. $SO^{2-}_4$
• D. $H_2O$

Answer 1

Answer: (C)

Nitration mixture contains equimolar ratio (i.e. $1: 1)$ of nitric acid and sulphuric acid.

It contains $\underset{+}{N}O _{2}, HSO _{4}^{-}$ and $H _{2} O$ species.

It does not contain $SO _{4}^{2-}$ ions.

This can be explained on the basis of generation of nitronium

$\overset{+}{N}O _{2}$ ion from nitrating mixture.

Generation of $\overset{+}{N}O _{2}$ ion

Step 1

Step II $H - \overset{\underset{|}{H}}{O^+} - NO_2 \ce{<=>} \overset{+}{N}O_2 + H_2O$