Question

The compound X in the reaction is
\[{\rm{X}} \overset{CH_{3}MgI}{\rightarrow}{\rm{Y}} \overset{Hydrolysis}{\rightarrow} {\rm{Mg(OH)I}} + {\rm{C}}{{\rm{H}}_{\rm{3}}}{\rm{COOH}}\]
A. HCHO
B. \[{\rm{C}}{{\rm{H}}_{\rm{3}}}{\rm{CHO}}\]
C. \[{\left( {{\rm{C}}{{\rm{H}}_{\rm{3}}}} \right)_2}{\rm{CO}}\]
D. \[{\rm{C}}{{\rm{O}}_{\rm{2}}}\]

Answer 1

Hint: Grignard reagent belongs to the class of organometallic compound. Its chemical formula is \[{\rm{R}} - {\rm{Mg}} - {\rm{X}}\] , where, R is for an alkyl group, Mg is for magnesium atom and X is for any halogen atom such as bromine, chlorine etc.

Complete step by step answer:
Let's understand the reaction of a Grignard reagent with Carbon dioxide. A Grignard reagent, when undergoing a reaction with carbon dioxide, then undergoes hydrolysis to give the product of carboxylic acid.
Let's understand the reaction mechanism of the reaction in detail. The first step is breaking of C-Mg bond and attack of C^- at the carbon atom of carbon dioxide. In the step, the carboxylate ion forms. Then, when the carboxylate ion undergoes a reaction with water, the formation of carboxylic acid occurs.

Image: Grignard reagent undergoes reaction with Carbon dioxide

Therefore, X is carbon dioxide. Hence, option B is the right answer.

Additional Information:
The preparation of the Grignard reagent is done from the reaction of magnesium and alkyl halide in the presence of ether (dry). Some of the reactions are,
(1)The reaction of aldehydes with Grignard reagent gives the product secondary alcohol.
(2)The reaction of ketones with Grignard reagent gives the product of tertiary alcohol.
(3)The reaction of esters with Grignard reagent gives the product of tertiary alcohol.

Note: The use of Grignard reagent to prepare chemo catalyst which is used in the chemical and pharmaceutical industries is very useful. In the agronomic industry, the development of eco-friendly products from Grignard reagents that possess soil-enriching properties results in a good market for Grignard reagents.