Match List-I with List-II.
| List-I (Reactants) | List-II (Main product) |
|---|---|
| (A) An alkyl halide and sodium in dry ether | (I) An alkylarene |
| (B) An alkyl halide, an aryl halide and sodium in dry ether | (II) An alkyl magnesium halide |
| (C) An aryl halide and sodium in dry ether | (III) An alkane with double the number of carbon atoms of the halide |
| (D) An alkyl halide and magnesium in dry ether | (IV) A compound with two aryl groups joined together |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A-III, B-I, C-IV, D-II
Alkyl and aryl halides react with active metals in dry ether. Sodium joins the organic groups of two halide molecules, while magnesium inserts itself between the carbon and the halogen.
(A) An alkyl halide and sodium in dry ether — This matches (III) An alkane with double the number of carbon atoms of the halide. This is the Wurtz reaction; two alkyl groups join, for example:
\( \displaystyle \ce{2CH3CH2Br + 2Na} \xrightarrow{\text{dry ether}} \ce{CH3CH2CH2CH3 + 2NaBr} \)
(B) An alkyl halide, an aryl halide and sodium in dry ether — This matches (I) An alkylarene. This is the Wurtz-Fittig reaction; an alkyl group joins the ring:
\( \displaystyle \ce{C6H5Cl + CH3Cl + 2Na} \xrightarrow{\text{dry ether}} \ce{C6H5CH3 + 2NaCl} \)
(C) An aryl halide and sodium in dry ether — This matches (IV) A compound with two aryl groups joined together. This is the Fittig reaction; chlorobenzene gives biphenyl:
\( \displaystyle \ce{2C6H5Cl + 2Na} \xrightarrow{\text{dry ether}} \ce{C6H5-C6H5 + 2NaCl} \)
(D) An alkyl halide and magnesium in dry ether — This matches (II) An alkyl magnesium halide. The product, RMgX, is a Grignard reagent, an organometallic compound:
\( \displaystyle \ce{CH3CH2Br + Mg} \xrightarrow{\text{dry ether}} \ce{CH3CH2MgBr} \)
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.”
“Alkyl halides react with sodium in dry ether to give hydrocarbons containing double the number of carbon atoms present in the halide. This reaction is known as Wurtz reaction.”
6.7.2 Reactions of Haloarenes – “A mixture of an alkyl halide and aryl halide gives an alkylarene when treated with sodium in dry ether and is called Wurtz-Fittig reaction.”
“Aryl halides also give analogous compounds when treated with sodium in dry ether, in which two aryl groups are joined together. It is called Fittig reaction.”