IIT-JEE 2012 · Paper 2 · Chemistry Q33

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ChemistrySingle correct+3 / -1Question 33 of 60

Passage

Paragraph for Questions 33 and 34

In the following reaction sequence, the compound J is an intermediate.
$\mathbf I\xrightarrow[\ce{CH3COONa}]{\ce{(CH3CO)2O}}\mathbf J\xrightarrow[\text{(ii) }\ce{SOCl2}\text{ (iii) anhyd. }\ce{AlCl3}]{\text{(i) }\ce{H2},\ \text{Pd/C}}\mathbf K$

J $(\ce{C9H8O2})$ gives effervescence on treatment with $\ce{NaHCO3}$ and a positive Baeyer's test.

The compound I is

Benzyl alcohol: a benzene ring with CH₂OH.

Acetophenone: a benzene ring with COCH₃.

Answer and worked solution

Official answer: A

What J is. $\ce{C9H8O2}$ with effervescence in $\ce{NaHCO3}$ (a carboxylic acid) and a positive Baeyer test (a C=C): cinnamic acid, $\ce{C6H5CH=CHCOOH}$ .

How it forms. Acetic anhydride with sodium acetate is the Perkin reaction, which converts an aromatic aldehyde into the α,β-unsaturated acid. So I is benzaldehyde.

(A)

Topics:Named reactions Carboxylic acids

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IIT-JEE 2012 · Paper 2, Chemistry question 33