Consider the following reaction sequence: HO - CH ₂- CH = CH ₂ [ (ii) NaHSO ₃] (i) OsO ₄ (A) KHSO ₄, (B) The major product (B) is:

Step-by-step solution

The starting material is allyl alcohol, HO - CH ₂- CH = CH ₂ . Reaction with OsO ₄ followed by NaHSO ₃ causes syn-dihydroxylation of the carbon-carbon double bond. This yields glycerol, HO - CH ₂- CH ( OH )- CH ₂- OH as product (A). Heating glycerol with a dehydrating agent like KHSO ₄ results in the elimination of two molecules of water. This dehydration process yields acrolein, H ₂ C = CH - CHO as the major product (B). Answer: H ₂ C = CH - CHO