Q.Predict the products A, B, X and Y in the following sequence of reactions: butan-2-ol --SOCl2--> A --Mg/ether--> B; butan-2-ol --Cu/573K--> X; B --X--> Y.

Step 1. Butan-2-ol + SOCl2 substitutes -OH for -Cl, giving A = 2-chlorobutane (sec-butyl chloride), CH3-CH2-CHCl-CH3.

Step 2. A + Mg/ether forms the Grignard reagent B = sec-butylmagnesium chloride, CH3-CH2-CH(MgCl)-CH3.

Step 3. Separately, butan-2-ol + Cu/573K (catalytic dehydrogenation of a SECONDARY alcohol, section 11.6.3) gives X = butan-2-one (methyl ethyl ketone), CH3-CO-CH2-CH3. …

Solve the two branches (SOCl2/Mg to a Grignard; Cu/573K to a ketone) independently first, then recognise that the SAME species X is the …

• Missing that 'X' is DELIBERATELY reused as both the product of the top (Cu/573K) branch AND the reagent that reacts with B in the bottom branch -- this is the key to solving the puzzle, not a typo. …