Explain the addition of a $Grignard$ reagent to aldehyde and ketone compounds.

(N/A) The reaction involves the nucleophilic addition of a $Grignard$ reagent $(R-Mg-X)$ to the carbonyl group $(C=O)$ of an aldehyde or ketone.
$1.$ The nucleophilic alkyl group $(R^-)$ of the $Grignard$ reagent attacks the electrophilic carbonyl carbon,while the electrophilic magnesium species $(Mg^+X)$ coordinates with the carbonyl oxygen,forming an intermediate addition product (alkoxymagnesium halide).
$2.$ Subsequent hydrolysis of this intermediate with water $(H_2O)$ yields an alcohol.
General reaction:
$R-Mg-X + >C=O$ $\rightarrow >C(R)-OMgX$ $\xrightarrow{H_2O} >C(R)-OH + Mg(OH)X$
Applications:
- $Methanal$ $(HCHO)$ reacts with $Grignard$ reagents to produce primary $(1^{\circ})$ alcohols.
- Other aldehydes $(RCHO)$ react to produce secondary $(2^{\circ})$ alcohols.
- Ketones $(R_2CO)$ react to produce tertiary $(3^{\circ})$ alcohols.