Statement I: Grignard reagents are obtained by the reaction of haloalkanes with magnesium metal in dry ether.
Statement II: A Grignard reagent reacts with water to give the corresponding alcohol.
In the light of the above statements, choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Only Statement I is correct.
A Grignard reagent, RMgX, is an organometallic compound. Its carbon pulls electrons from magnesium, so the alkyl carbon is electron rich and takes up a proton from any source of protons; this is why even traces of moisture must be kept away and the reagent is made in dry ether.
Statement I: Grignard reagents are obtained by the reaction of haloalkanes with magnesium metal in dry ether. — True. The haloalkane reacts with magnesium in dry ether:
\( \displaystyle \ce{R-X + Mg} \xrightarrow{\text{dry ether}} \ce{R-Mg-X} \)
Statement II: A Grignard reagent reacts with water to give the corresponding alcohol. — False. Water is acidic enough to give a proton to the alkyl group, so the product is the hydrocarbon, not an alcohol:
\( \displaystyle \ce{RMgX + H2O -> RH + Mg(OH)X} \)
NCERT (2026-27 edition):
6.7.1 Reactions of Haloalkanes – “…An important class of organo-metallic compounds discovered by Victor Grignard in 1900 is alkyl magnesium halide, RMgX, referred as Grignard Reagents. These reagents are obtained by the reaction of haloalkanes with magnesium metal in dry ether.”
“Grignard reagents are highly reactive and react with any source of proton to give hydrocarbons. Even water, alcohols, amines are sufficiently acidic to convert them to corresponding hydrocarbons.”
“It is therefore necessary to avoid even traces of moisture from a Grignard reagent. That is why reaction is carried out in dry ether.”