Grignard addition to carbonyl compounds is specific case of nucleophillic addition reaction which leads to formation of all type of alcohols (1^(@),2^(@) & 3^(@)) .In this addition the strongly nucleophlic Grignard reagent uses its electron pair to form a bond with theC - atom ofgtC=O group, where one e^(-) pair of group ,shifts out towards oxygen . It results in the formation of an intermediate species in which alkoxide ion associated withMg^(2+) and . Now addition of an intermediate of this species to give alcohol.Here P andQare respectively :

Grignard addition to carbonyl compounds is specific case of nucleophil

1.	Grignard addition to carbonyl compounds is specific case of nucleophillic addition reaction which leads to formation of all type of alcohols (1^(@),2^(@) & 3^(@)) .In this addition the strongly nucleophlic Grignard reagent uses its electron pair to form a bond with theC - atom ofgtC=O group, where one e^(-) pair of group ,shifts out towards oxygen . It results in the formation of an intermediate species in which alkoxide ion associated withMg^(2+) and . Now addition of an intermediate of this species to give alcohol.Here P andQare respectively :
Answer» SOLUTION : DIOL PROTECTS aldehyde since it is more REACTIVE. Grignard reagent reacts with keto carbon carbon since it does not REACT with (only oneequalent is given)