An organic compound (X) has the molecular formula C5H10O. Draw structures for (X) if it: (I) does not give Tollen's test but gives a positive iodoform test; (II) does not give Tollen's test and iodoform test but undergoes Aldol condensation; (III) undergoes Cannizzaro's reaction.
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Solution and Explanation
Answer:
(I) No Tollen's test means it is a ketone (not an aldehyde). Positive iodoform means it has a CH3-CO- group. So (X) is pentan-2-one, CH3-CO-CH2-CH2-CH3.
(II) No Tollen's and no iodoform means it is a ketone with no methyl directly on the carbonyl, but it must have alpha-hydrogens to do Aldol. So (X) is pentan-3-one, CH3-CH2-CO-CH2-CH3.
(III) Cannizzaro is given by an aldehyde with no alpha-hydrogen. So (X) is 2,2-dimethylpropanal (pivaldehyde), (CH3)3C-CHO, where the carbon next to -CHO carries three methyl groups and no hydrogen.
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