See image — Alcohols Phenols and Ethers Chemistry Question

💡 Solution & Explanation

Concept: Active hydrogen atoms (those bonded to electronegative atoms like O, N, S) react with Grignard reagents (RMgX) to produce one mole of alkane per active hydrogen. The reaction is: R-OH + CH3MgI → CH4 + R-OMgI. Step 1: Find moles of compound. Molecular formula C3H8O3, MW = 3(12) + 8(1) + 3(16) = 36 + 8 + 48 = 92 g/mol. Moles of compound = 0.092 g / 92 g/mol = 0.001 mol. Step 2: Find moles of CH4 produced. At STP, 1 mole of gas occupies 22400 mL. Moles of CH4 = 67.00 mL / 22400 mL/mol = 0.002991 mol ≈ 0.003 mol. Step 3: Determine number of active hydrogens per molecule. Number of active H per molecule = moles of CH4 / moles of compound = 0.003 / 0.001 = 3. Step 4: Verify with structure. C3H8O3 with three active hydrogens (three -OH groups) corresponds to glycerol (propane-1,2,3-triol: HOCH2-CH(OH)-CH2OH), which indeed has three hydroxyl groups, each contributing one active hydrogen. Why other options fail: - (a) one and (b) two: would give only 22.4 mL or 44.8 mL of CH4, not 67 mL. - (d) four: would give 89.6 mL of CH4, not 67 mL. Therefore, the correct answer is C.