Concept:

Both alcohols and carboxylic acids possess active acidic hydrogen attached to oxygen, reacting with active alkali metals like sodium (Na) to evolve \(\text{H}_2\) gas. When an alcohol and a carboxylic acid react together in the presence of an acid catalyst, they undergo esterification to form an ester, characterized by a distinct sweet fruity fragrance.

Reactions:

$$2\,\text{R-OH} + 2\,\text{Na} \longrightarrow 2\,\text{R-ONa} + \text{H}_2 \uparrow$$

$$2\,\text{R-COOH} + 2\,\text{Na} \longrightarrow 2\,\text{R-COONa} + \text{H}_2 \uparrow$$

$$\text{R-COOH} + \text{R'-OH} \overset{\text{H}^+}{\rightleftharpoons} \text{R-COOR}' \text{ (Ester, Fruity Smell)} + \text{H}_2\text{O}$$

Solution:

• Because both X and Y liberate \(\text{H}_2\) gas with metallic sodium, they must be an alcohol and a carboxylic acid.



• When X and Y react together, the resultant compound Z gives a pleasant fruity aroma, identifying Z unequivocally as an ester.



• Matching the choices: X = Alcohol, Y = Acetic Acid (a carboxylic acid), and Z = Ester, which corresponds to Option C.

Why other options are incorrect:

• Option A & Option B: Esters cannot react with sodium metal to evolve hydrogen gas, so Y cannot be an ester. Mineral acids are inorganic compounds.
• Option D: Mineral acids are inorganic and do not form organic esters with fruity smell when classified as Y in this organic context.