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 FeSO4, followed by acidification with conc. H2SO4, 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 NaHCO3 results in effervescence.
(IV) Caprolactam	(S) The compound reacts with bromine water to give a white precipitate.
	(T) Treating the compound with neutral FeCl3 solution produces violet color.

Correct Option: I → P, S; II → T; III → Q, R; IV → P

To match each compound in LIST-I with its correct qualitative test observation in LIST-II, let us analyze the functional groups and elements present in each compound step-by-step:

1. Compound (I): Aniline

Aniline is an aromatic primary amine containing Nitrogen (N) bound to a benzene ring.

• Lassaigne's Test for Nitrogen (P): Aniline contains nitrogen. In Lassaigne's sodium fusion test, nitrogen reacts with sodium and carbon to form sodium cyanide (NaCN). When boiled with ferrous sulfate (FeSO₄) and acidified with concentrated H₂SO₄, it forms Prussian blue precipitate [Fe₄[Fe(CN)₆]₃]. Hence, Aniline matches with (P).

• Bromine Water Test (S): Due to the strong activating nature of the -NH₂ group on the benzene ring, aniline undergoes rapid electrophilic aromatic substitution with bromine water to form a white precipitate of 2,4,6-tribromoaniline. Hence, Aniline also matches with (S).

Thus, I → P, S.

2. Compound (II): o-Cresol

o-Cresol is a phenolic compound containing a phenolic -OH group attached to the aromatic ring.

• Neutral FeCl₃ Test (T): Phenols react with neutral ferric chloride (FeCl₃) solution to form a characteristic violet-colored complex [Fe(OC₆H₄CH₃)₆]^3-. Hence, o-Cresol matches with (T).

Thus, II → T.

3. Compound (III): Cysteine

Cysteine is an amino acid with the formula HS-CH₂-CH(NH₂)-COOH containing both Nitrogen (N) and Sulfur (S) as well as a carboxylic acid (-COOH) group.

• Lassaigne's Test for N and S present together (Q): When both nitrogen and sulfur are present in an organic compound, sodium fusion converts them into sodium thiocyanate (NaSCN). Upon treatment with ferric ions or sodium nitroprusside in specific acidic/alkaline conditions, it gives a characteristic blood-red coloration [Fe(SCN)]²⁺. Hence, Cysteine matches with (Q).

• NaHCO₃ Effervescence Test (R): Cysteine contains a carboxylic acid group (-COOH), which reacts with saturated sodium bicarbonate (NaHCO₃) solution to release carbon dioxide gas (CO₂), producing brisk effervescence. Hence, Cysteine also matches with (R).

Thus, III → Q, R.

4. Compound (IV): Caprolactam

Caprolactam is a cyclic amide containing Nitrogen (N) in its ring structure.

• Lassaigne's Test for Nitrogen (P): Since it contains nitrogen, its sodium fusion extract forms NaCN, which yields a Prussian blue color upon boiling with FeSO₄ followed by acidification with concentrated H₂SO₄. Hence, Caprolactam matches with (P).

Thus, IV → P.

Combining all the correct matches gives:

I → P, S; II → T; III → Q, R; IV → P