Reaction types in multi-stage organic synthesis Steps:

• Examine the first equation to identify if it involves adding atoms across a multiple bond (addition) or replacing a group (substitution).
• Examine the second equation to classify it as substitution, where a functional group like halide is replaced by hydroxide.
• Match the sequence to options: addition followed by substitution fits B.
• Confirm no other sequence (e.g., elimination) matches the conversion to propan-1-ol.

Not enough information: Equations not provided, so reaction types cannot be verified precisely.

Why B is correct:

• Addition introduces a functional group (e.g., HBr across alkene from prior step), followed by substitution (e.g., OH⁻ replacing Br in alkyl halide, per SN2 mechanism).

Why the others are wrong:

• A: Starts with addition but second is elimination, which would yield alkene, not alcohol.
• C: Elimination first removes atoms to form alkene, but substitution second doesn't fit typical alcohol formation sequence.
• D: Substitution first (e.g., halogenation) then elimination yields alkene, missing addition for alcohol.

Final answer: B