JEE Advanced 2022 — Paper 1 — CHEM-III solution

JEE Advanced2022Paper 1CHEM-III

Match the compounds in LIST-I with the observations in LIST-II, and choose the correct option.

LIST-I	LIST-II
(I) Aniline	(P) Sodium fusion extract of the compound on boiling with FeSO $_{4}$ , followed by acidification with conc. H $_{2}$ SO $_{4}$ , gives Prussian blue color.
(II) o-Cresol	(Q) Sodium fusion extract of the compound on treatment with sodium nitroprusside gives blood red color.
(III) Cysteine	(R) Addition of the compound to a saturated solution of NaHCO $_{3}$ results in effervescence.
(IV) Caprolactam	(S) The compound reacts with bromine water to give a white precipitate.
	(T) Treating the compound with neutral FeCl $_{3}$ solution produces violet color.

A
I $\to$ P, Q; II $\to$ S; III $\to$ Q, R; IV $\to$ P
B
I $\to$ P; II $\to$ R, S; III $\to$ R; IV $\to$ Q, S
C
I $\to$ Q, S; II $\to$ P, T; III $\to$ P; IV $\to$ S
D
I $\to$ P, S; II $\to$ T; III $\to$ Q, R; IV $\to$ P

Solution

(I) Aniline (C $_{6}$ H $_{5}$ NH $_{2}$ ): contains nitrogen, so the Lassaigne sodium fusion test gives the Prussian blue colour with FeSO $_{4}$ and conc. H $_{2}$ SO $_{4}$ (P). Aniline also reacts readily with bromine water at the ortho and para positions to give 2,4,6-tribromoaniline as a white precipitate (S).

(II) o-Cresol (2-methylphenol):

Being a phenol, it gives a characteristic violet colour with neutral FeCl $_{3}$ (T).

(III) Cysteine:

It contains both nitrogen and sulphur. The sodium fusion extract contains sulphide (from S) which gives a blood-red colour with sodium nitroprusside (Q). It also has a –COOH group, so it gives effervescence with saturated NaHCO $_{3}$ as CO $_{2}$ is released (R).

(IV) Caprolactam:

It is a cyclic amide containing nitrogen. Its sodium fusion extract gives cyanide which, with FeSO $_{4}$ followed by conc. H $_{2}$ SO $_{4}$ acidification, produces the Prussian blue colour (P).

The correct matching is option (D).

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