An unknown alkene 'X' undergoes two different reaction sequences: Sequence 1: 'X' is treated with B ₂ H ₆ followed by H ₂ O ₂/ OH ^- , and the resulting product is oxidized with Pyridinium chlorochromate (PCC) to give compound 'Y'. Compound 'Y' gives a positive Tollens' test but a negative iodoform test. Sequence 2: 'X' is subjected to acid-catalyzed hydration, and the resulting product is oxidized with CrO ₃ to give

Step-by-step solution

For Sequence 1, hydroboration-oxidation followed by PCC yields an aldehyde 'Y' (since it gives a positive Tollens' test). This indicates that 'X' must be a terminal alkene, and 'Y' cannot be ethanal (as ethanal gives a positive iodoform test). For Sequence 2, acid-catalyzed hydration followed by CrO ₃ oxidation yields a methyl ketone 'Z' (since it gives a positive iodoform test but a negative Tollens' test). Let us evaluate the given options: 1) Ethene: Sequence 1 yields ethanal, which gives a positive iodoform tes