Animated Solution for Chemistry - Organic Chemistry: The correct match between Item-I and Item-II is\n\n$\begin{array}{llll}& \text{Item-I (Drug)}& & \text{Item-II (Test)}\\ \text{A.}& \text{Chloroxylenol}& \text{P.}& \text{Carbylamine test}\\ \text{B.}& \text{Norethindrone}& \text{Q.}& \text{Sodium hydrogen carbonate test}\\ \text{C.}& \text{Sulphapyridine}& \text{R.}& \text{Ferric chloride test}\\ \text{D.}& \text{Penicillin}& \text{S.}& \text{Bayer’s test}\end{array}$

The problem asks us to match four well-known pharmaceutical drugs with the chemical tests used to identify their characteristic functional groups. This is a classic question that bridges the concepts from "Chemistry in Everyday Life" with the practical qualitative analysis techniques from "Principles Related to Practical Chemistry".

You might recognize it as the active antiseptic ingredient in Dettol. If we examine its chemical structure, it is a substituted phenol (specifically, 4-chloro-3,5-dimethylphenol). The key functional group here is the phenolic $-OH$ group.

How do we test for phenols in the laboratory? The standard method is the Ferric chloride ($FeC{l}_3$) test. When a phenol reacts with neutral $FeC{l}_3$ solution, it forms a complex that gives a characteristic violet, blue, or green colouration. Therefore, Chloroxylenol will give a positive Ferric chloride test. This means Item A matches with Item R.

Its molecular structure is a steroid nucleus that features multiple bonds, specifically an $\alpha ,\beta$-unsaturated ketone (a $C=C$ double bond) and a terminal alkyne (a $C\equiv C$ triple bond).

To detect this unsaturation, we use Baeyer's reagent, which is a cold, dilute, alkaline solution of potassium permanganate ($KMn{O}_4$). When an unsaturated compound reacts with Baeyer's reagent, the deep pink colour of $KMn{O}_4$ gets discharged as it is reduced to a brown precipitate of manganese dioxide ($Mn{O}_2$). Thus, Norethindrone will respond to Baeyer's test. This means Item B matches with Item S.

The critical functional group for our analysis is the primary aromatic amine ($-N{H}_2$) group attached directly to the benzene ring.

The most famous and definitive test for primary amines (both aliphatic and aromatic) is the Carbylamine test (also known as the Hofmann isocyanide synthesis). When a primary amine is heated with chloroform ($CHC{l}_3$) and alcoholic potassium hydroxide ($KOH$), it produces an isocyanide (carbylamine), which has an unmistakably foul and pungent smell. Therefore, Sulphapyridine will give a positive Carbylamine test. This means Item C matches with Item P.

While Penicillin has a complex structure including a $\beta$-lactam ring and a thiazolidine ring, it also contains a free carboxylic acid ($-COOH$) group.

Carboxylic acids are relatively strong organic acids. When treated with a weak base like sodium bicarbonate ($NaHC{O}_3$), they undergo an acid-base reaction to form a sodium salt, water, and carbon dioxide gas. The rapid evolution of $C{O}_2$ gas is observed as brisk effervescence. Therefore, Penicillin will give a positive Sodium hydrogen carbonate test. This means Item D matches with Item Q.

Putting it all together, we have established the following matches based on the functional groups present in each drug: A (Chloroxylenol) $\to$ R (Ferric chloride test) B (Norethindrone) $\to$ S (Baeyer's test) C (Sulphapyridine) $\to$ P (Carbylamine test) D (Penicillin) $\to$ Q (Sodium hydrogen carbonate test)

Looking at the given options, this sequence perfectly matches option (b).