Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Aniline on nitration yields ortho, meta & para nitro derivatives of aniline.
Reason R: Nitrating mixture is a strong acidic mixture.
In the light of the above statements, choose the correct answer from the options given below

Explanation: Aniline contains an amino group $$\mathrm{(-NH_2)}$$ directly attached to the benzene ring. The $$\mathrm{-NH_2}$$ group is normally an activating and ortho/para-directing group.

However, direct nitration of aniline gives a mixture containing significant amounts of meta product:

$$\mathrm{para\text{-}nitroaniline \approx 51%}$$

$$\mathrm{meta\text{-}nitroaniline \approx 47%}$$

$$\mathrm{ortho\text{-}nitroaniline \approx 2%}$$

Hence, the Assertion is correct.

The nitrating mixture consists of concentrated $$\mathrm{HNO_3}$$ and concentrated $$\mathrm{H_2SO_4}$$, making the medium strongly acidic.

Aniline behaves as a base and gets protonated to form the anilinium ion:

$$\mathrm{C_6H_5NH_2 + H^+ \rightarrow C_6H_5NH_3^+}$$

The $$\mathrm{-NH_3^+}$$ group is strongly deactivating and meta-directing.

Therefore, a large fraction of the reaction occurs through the meta-directing anilinium ion, producing substantial amounts of meta-nitroaniline.

Hence, both Assertion and Reason are correct, and the Reason correctly explains the Assertion.