Step 1: The compound X is an aromatic methyl ketone, most likely acetophenone (C\(_6\)H\(_5\)COCH\(_3\)) with molecular formula C\(_8\)H\(_8\)O.
Step 2: When heated with concentrated KOH, X undergoes Cannizzaro-type reaction (if it were formaldehyde) or more likely aldol condensation-disproportionation to form Y, a hydrocarbon with two alkyl groups (isopropyl benzene).
Step 3: Reduction of X with NaBH\(_4\) gives a secondary alcohol, i.e., \chemfig{Ph-CH(OH)CH3}.
Step 4: So, Y is isopropyl benzene and Z is 1-phenylethanol.