Read the passage given below to answer questions:
Most of haloalkanes and haloarenes react with certain metals to give compound containing carbon metal bonds called organometallic compounds. Grignard reagent is such organomagnesium compound. Grignard reagent can be prepared from halogen derivative of alkanes/arenes with magnesium metal in dry ether. These are highly reactive compounds and react with source of proton to give hydrocarbon. Grignard reagents undergo addition with carbonyl compounds to give corresponding alcohols.
The correct equation from the following representing the preparation of phenyl magnesium bromide is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → C6H5Br + Mg (dry ether)
Grignard reagents are made by treating a halogen compound with magnesium metal in dry ether:
\( \ce{C6H5Br + Mg} \xrightarrow{\text{dry ether}} \ce{C6H5MgBr} \)
The ether must be dry because water (and any other source of protons) converts the Grignard reagent into the hydrocarbon.
Why the other options are incorrect
Option (1) — Incorrect. Sodium phenoxide and \( \ce{MgBr2} \) contain no C–Mg or C–Br bond to form one.
Option (3) — Incorrect. Starts from an organomagnesium compound and uses alcohol, which would destroy a Grignard reagent.
Option (4) — Incorrect. \( \ce{MgCl2} \) is not magnesium metal, and acetic acid would protonate any Grignard reagent formed.
NCERT (2026-27 edition):
Reaction with Metals
