0.1 mole of compound 'S' will weigh ______ g. (Given molar mass in $\mathrm{g} \mathrm{mol}^{-1}$ C: 12, H: 1, O: 16)

JEE Main · 2025 · 29 Jan 2025 · Shift 1 · Some Basic Concepts of Chemistry

0.1 mole of compound 'S' will weigh ______ g.
(Given molar mass in

g mol^{- 1}

C: 12, H: 1, O: 16)

Answer: 13

The sequence takes a cyclic 1,2-diol through oxidative ring-cleavage by excess

Cr O_{3}

to a diketo-diacid P, which cyclises intramolecularly under acid catalysis to a hemiketal (lactol) Q. Addition of

C H_{3} MgI

to the carbonyl of Q, followed by acidic work-up with loss of methane, opens the ring to give R, and reduction of the remaining carbonyl in R with

NaB H_{4}

H_{2} O

delivers the alcohol S, a compound of molar mass

130 g mol^{- 1}

0.1 mol \times 130 g mol^{- 1} = 13 g

JEE Main · 2025 · 29 Jan 2025 · Shift 1 · Integer answer