P gives positive iodoform (has CH3CO−) but negative Tollen's (no −CHO).
Q (after acid hydrolysis) gives both tests, meaning Q has both CH3CO− and −CHO.
This indicates P has an acetal protecting an aldehyde group.
Option (1): CH3−CO−CH2−CH(OCH3)2
Has CH3CO− → positive iodoform
Has acetal −CH(OCH3)2, no free aldehyde → negative Tollen's
Hydrolysis: −CH(OCH3)2H+/H2O−CHO
Q = CH3−CO−CH2−CHO gives both iodoform and Tollen's test
Molecular formula: C6H12O3



