Question

Learners will be able to perform and/or describe the following regarding Grignard reactions:

• Reaction to form and consume a Grignard reagent;
• Reactions of a carbonyl compound with a Grignard reagent to form an alcohol;
• Know the difference between nucleophilic reactions and electrophilic reactions; and
• Perform a Grignard synthesis with reasonable yield.

Which statement properly states how a Grignard reaction occurs?

A. The electrophilic Grignard reagent reacts with the nucleophilic carbonyl compound (i.e. aldehyde or ketone).

B. The electrophilic Grignard reagent reacts with the electrophilic carbonyl compound (i.e. aldehyde or ketone).

C. The nucleophilic Grignard reagent reacts with the nucleophilic carbonyl compound (i.e. aldehyde or ketone).

D. The nucleophilic Grignard reagent reacts with the electrophilic carbonyl compound (i.e. aldehyde or ketone).

Answer 1

Grignard reagent is known as R-Mg-X. R can be alkyl or aryl group.

The electronegativity of magnesium is less than electronegativity of carbon. When carbon form bond with magneisum, the carbon becomes nucleophile. Hence Grignard reagent is nucleophile.

In carbonyl compounds, carbon has double bond with oxygen. Oxygen is more electronegative than carbon. Hence carbonyl carbon is electrophile.

Considering the above points the correct answer is The nucleophilic Grignard reagent reacts with the electrophilic carbonyl compound (i.e. aldehyde or ketone).

Hence option D is correct answer