Match the entries of column I with appropriate entries of column II and choose the correct option out of the four options given.

(i)-(b), (ii)-(a), (iii)-(d), (iv)-(c)

The correct answer is option 4. (i)-(b), (ii)-(a), (iii)-(d), (iv)-(c).

Let us delve into the explanations for each pair in Column I matched with Column II:

(i) Benzenesulphonyl chloride → (b) Hinsberg reagent

Benzenesulphonyl chloride is commonly known as the Hinsberg reagent in organic chemistry. It is used as a reagent to distinguish between primary, secondary, and tertiary amines through their reaction products:

Primary amines react with benzenesulphonyl chloride to form N-alkylbenzenesulfonamides, which are soluble in alkali but insoluble in acid.

Secondary amines react to form N,N-dialkylbenzenesulfonamides, which are soluble in both alkali and acid.

Tertiary amines do not react with benzenesulphonyl chloride under normal conditions.

(ii) Sulphanilic acid → (a) Zwitter ion

Sulphanilic acid is an aromatic sulfonic acid. In its crystalline form, it exists as a zwitterion, which is a molecule with both positive and negative charges:

In the case of sulphanilic acid, the sulfonic acid group \((-SO_3H)\) is acidic and can lose a proton \((H^+)\) to become negatively charged (anion). The amino group \((-NH_2)\) can gain a proton \((H^+)\) to become positively charged (cation). Therefore, in its crystalline form, sulphanilic acid can exist as a zwitterion due to the balance between these charges.

(iii) Alkyldiazonium salts → (d) Conversion to alcohols

Alkyldiazonium salts can decompose under certain conditions to liberate nitrogen gas \((N_2)\) and form alcohols:

Alkyldiazonium salts have the general structure \(R-N_2^+X^-\) (where \(R\) is an alkyl group). When treated with water or under conditions where the diazonium group \((N_2^+)\) decomposes, the alkyl group \((R)\) can be converted into an alcohol \((ROH)\).

(iv) Aryldiazonium salts → (c) Dyes

Aryldiazonium salts are versatile intermediates in organic synthesis, particularly in the formation of azo dyes:

Aryldiazonium salts have the general structure Ar-N2+X- (where Ar is an aryl group). They undergo coupling reactions with aromatic compounds or phenols to form azo dyes (compounds containing the functional group \(-N=N-\)).