Match the reaction in List I (each uses bromoethane as substrate) with the major product in List II, and choose the correct combination. List I: P CH3CH2Br + NaCN in DMSO; Q CH3CH2Br + AgCN; R CH3CH2Br + AgNO2; S CH3CH2Br + KSCN in ethanol (attack through the softer, sulfur end). List II: 1 CH3CH2-NC; 2 CH3CH2-NO2; 3 CH3CH2-CN; 4 CH3CH2-S-CN; 5 CH3CH2-O-N=O.

MolSynapse / Question bank / Organic Reaction Mechanisms III: Nucleophilic Substitution / SN1 vs SN2: substrate, nucleophile, solvent, leaving group

JEE Advanced levelSingle correct optionDifficulty 3 of 3o3103

Match the reaction in List I (each uses bromoethane as substrate) with the major product in List II, and choose the correct combination. List I: P $CH X_{3} CH X_{2} Br + NaCN$ in DMSO; Q $CH X_{3} CH X_{2} Br + AgCN$ ; R $CH X_{3} CH X_{2} Br + AgNO X_{2}$ ; S $CH X_{3} CH X_{2} Br + KSCN$ in ethanol (attack through the softer, sulfur end). List II: 1 $CH X_{3} CH X_{2} - NC$ ; 2 $CH X_{3} CH X_{2} - NO X_{2}$ ; 3 $CH X_{3} CH X_{2} - CN$ ; 4 $CH X_{3} CH X_{2} - S - CN$ ; 5 $CH X_{3} CH X_{2} - O - N = O$ .

AP-1, Q-3, R-5, S-4
BP-3, Q-4, R-2, S-1
CP-3, Q-1, R-2, S-4
DP-3, Q-1, R-5, S-2

Answer: C

Ionic sodium cyanide attacks through carbon to give the nitrile (3). Covalent silver cyanide reacts through nitrogen to give the isocyanide (1). Silver nitrite gives the nitroalkane (2) through nitrogen. Thiocyanate attacks through its softer sulfur terminus in SN2 and gives the alkyl thiocyanate (4). The alkyl nitrite (5) is not the major product of the silver salt.

Practice Organic Reaction Mechanisms III: Nucleophilic Substitution More on SN1 vs SN2: substrate, nucleophile, solvent, leaving group

Previous questionNext question

Answer: C

More questions on SN1 vs SN2: substrate, nucleophile, solvent, leaving group