JEE Main · 2023 · 29 Jan 2023 · Shift 2 · Some Basic Concepts of Chemistry

Sodium reacts with water to give sodium hydroxide in a one-to-one ratio, and $0.69$ g of sodium is $\frac{0.69}{23}=0.03$ mol, so $0.03$ mol of sodium hydroxide is formed. Neutralisation with hydrochloric acid also proceeds one-to-one, requiring $0.03$ mol of hydrogen chloride. The acid contains $73\mathrm{g}{\mathrm{L}}^{-1}$, which is $\frac{73}{36.5}=2$ mol per litre, so the volume needed is $\frac{0.03}{2}=0.015$ L, that is $15$ mL.