See image — Reaction Mechanism Chemistry Question

💡 Solution & Explanation

Concept: The Hofmann bromamide (Hofmann rearrangement) reaction involves the conversion of a primary amide to a primary amine with one fewer carbon. The balanced equation requires determining the stoichiometric coefficient x for NaOH. Step 1: Write the overall reaction as given: R-C(=O)-NH2 + xNaOH + Br2 → R-NH2 + 2NaBr + Na2CO3 + H2O Step 2: Balance atoms and charges to find x. Left side species: R-CONH2, xNaOH, Br2 Right side species: R-NH2, 2NaBr, Na2CO3, H2O Step 3: Count sodium (Na) atoms: Right side: 2NaBr gives 2 Na, Na2CO3 gives 2 Na → total Na = 4 Left side: xNaOH gives x Na Therefore x = 4. Step 4: Verify by counting other atoms with x = 4: - Bromine: Left = 2 (from Br2); Right = 2 (from 2NaBr). ✓ - Carbon: Left = 1 (carbonyl C in amide) + R; Right = R (in R-NH2) + 1 (in Na2CO3). ✓ - Oxygen: Left = 1 (C=O) + 4 (from 4NaOH) = 5; Right = 3 (Na2CO3) + 1 (H2O) = 4. Need to recheck. Actually: Left O = 1 (amide C=O) + 4×1 (NaOH) = 5; Right O = 3 (Na2CO3) + 1 (H2O) = 4. Difference of 1 — this is consistent if we check hydrogen balance. - Hydrogen: Left = 2 (NH2) + 4 (NaOH) = 6; Right = 2 (R-NH2) + 2 (H2O) = 4. Hmm, let me recount. Left H: amide NH2 = 2H, 4NaOH = 4H → total = 6H Right H: R-NH2 = 2H, H2O = 2H → total = 4H. Discrepancy of 2H suggests coefficient of H2O may be 2, but the equation as written shows H2O (not 2H2O). The equation in the problem is a simplified/overall representation where exact H2O coefficient may not be balanced precisely, but the Na count is unambiguous. Step 5: The unambiguous balance from sodium atoms gives x = 4, confirming option (b). Why other options fail: - (a) 3: Only 3 Na on left but 4 needed on right. ✗ - (c) 5: Excess Na unaccounted for. ✗ - (d) 6: Excess Na unaccounted for. ✗ Therefore, the correct answer is B.