Grignard reagent
Grignard reagent is a strong nucleophile and a powerful base that readily reacts with carbonyl compounds such as acetaldehyde and acetone. Here's why Grignard reagent is the reagent with which both acetaldehyde and acetone react easily:

Formation of Grignard reagent
- Grignard reagents are formed by reacting alkyl or aryl halides with magnesium metal in anhydrous ether. The resulting Grignard reagent has the general formula RMgX, where R is an alkyl or aryl group and X is a halogen atom.
- The presence of the Mg-X bond in the Grignard reagent imparts it with high reactivity towards carbonyl compounds.

Reaction with acetaldehyde
- Acetaldehyde is a carbonyl compound with the formula CH3CHO. When a Grignard reagent such as RMgX reacts with acetaldehyde, the oxygen atom of the carbonyl group attacks the carbon atom of the Grignard reagent to form a new carbon-carbon bond.
- The resulting product is a secondary alcohol.

Reaction with acetone
- Acetone is a ketone with the formula (CH3)2CO. When a Grignard reagent reacts with acetone, a similar nucleophilic addition reaction occurs, leading to the formation of a tertiary alcohol.
- The resulting alcohol product is formed by the addition of the Grignard reagent to the carbonyl carbon of acetone.
In conclusion, the Grignard reagent is a versatile reagent that can easily react with both acetaldehyde and acetone to form alcohol products. Its strong nucleophilic and basic properties make it an ideal reagent for the addition reactions with carbonyl compounds.