Match List-I with List-II
|
List-I |
List-II |
|
(A) Gatterman-Koch reaction |
(I) \( CrO_2Cl_2/CS_2 \) |
|
(B) Rosenmund reduction |
(II) Acyl chloride and anhyd. \( AlCl_3 \) |
|
(C) Etard reaction |
(III) \( CO, HCl, AlCl_3/CuCl \) |
|
(D) Friedel Craft acylation |
(IV) \( H_2/Pd-BaSO_4 \) |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
These are named reactions for making aldehydes and ketones, each identified by its reagent. Gatterman-Koch and Etard put a –CHO group on an aromatic ring (from benzene and from toluene); Rosenmund reduces an acid chloride to an aldehyde; Friedel-Crafts acylation puts an acyl group on the ring and gives a ketone.
(A) Gatterman-Koch reaction — This matches (III) \(CO, HCl, AlCl_3/CuCl\). Benzene with carbon monoxide and hydrogen chloride, catalysed by anhydrous \( \ce{AlCl3} \) or CuCl, gives benzaldehyde.
\( \displaystyle \ce{C6H6 + CO + HCl} \xrightarrow{\text{anhyd. }\ce{AlCl3}/\ce{CuCl}} \ce{C6H5CHO} \)
(B) Rosenmund reduction — This matches (IV) \(H_2/Pd-BaSO_4\). An acyl chloride is hydrogenated over palladium on barium sulphate; the poisoned catalyst stops at the aldehyde.
\( \displaystyle \ce{C6H5COCl + H2} \xrightarrow{\ce{Pd-BaSO4}} \ce{C6H5CHO + HCl} \)
(C) Etard reaction — This matches (I) \(CrO_2Cl_2/CS_2\). Chromyl chloride in \( \ce{CS2} \) oxidises the methyl group of toluene to a chromium complex, which is hydrolysed to benzaldehyde.
\( \displaystyle \ce{C6H5CH3} \xrightarrow[\text{(ii) }\ce{H3O+}]{\text{(i) }\ce{CrO2Cl2},\ \ce{CS2}} \ce{C6H5CHO} \)
(D) Friedel Craft acylation — This matches (II) Acyl chloride and anhyd. \(AlCl_3\). The Lewis acid forms an acylium ion from the acyl chloride, which substitutes into benzene to give a ketone.
\( \displaystyle \ce{C6H6 + CH3COCl} \xrightarrow{\text{anhyd. }\ce{AlCl3}} \ce{C6H5COCH3 + HCl} \)
Shortcut: (A)-(III) appears only in Option (4).