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A GRIGNARD REAGENT is formed by reacting an alkyl halide with
Asodium metal in dry ether
Bmagnesium metal in dry ether
Czinc dust in acetic acid
Dlithium in liquid ammonia
Answer & Solution
Correct answer: B. magnesium metal in dry ether
1. NCERT §6.5 (Reactions): a Grignard reagent has the general formula $\mathrm{R{-}MgX}$ (alkyl magnesium halide).
2. Preparation: $\mathrm{R{-}X} + \mathrm{Mg} \xrightarrow{\text{dry ether}} \mathrm{R{-}MgX}$.
3. The dry ether is CRUCIAL — moisture would destroy the Grignard. Ether also stabilises the organo-magnesium species through Lewis-base coordination.
4. Grignard reagents are extremely useful — they add to carbonyl compounds to give alcohols of arbitrary length, used in countless syntheses.
5. Option A is the Wurtz reaction (gives a coupled alkane, not a Grignard). Option C is for organozinc (Reformatsky reagent). Option D is for the Birch reduction conditions, not Grignard.
_Source: NCERT Class 12 Chemistry Part 2, Ch 6, §6.5 (Grignard reagent preparation), p. 14–15._
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