Grignard Reagent with Carbonyl Compounds

Predict the major organic product(s) for each of the following reactions: (a) CH3MgBr + formaldehyde (HCHO), followed by H3O+. (b) CH3CH2MgBr + acetone (CH3COCH3), followed by H3O+. (c) PhenylMgBr + CO2, followed by H3O+. Explain the pattern in terms of the relationship between the carbonyl compound and the resulting alcohol.