Question

A compound 'A'with molecular formula ${C_5H_{10}O}$gives a positive ${2,4-DNP}$ test but a negative Tollen's test. On treatment with sodium hypochlorite, it gives ${CHCl_3}$ and compound 'B'. Compound 'B' is

• A. Sodium propanoate
• B. Sodium butanoate
• C. Sodium acetate
• D. ${n-Butane}$

Answer 1

Answer: (B)

Sodium butanoate

Answer 2

The correct answer is option (b): Sodium butanoate

Positive 2,4-Dinitrophenylhydrazine (${2,4-DNP}$) test: Compound 'A' gives a positive ${2,4-DNP}$ test, indicating the presence of a carbonyl group, which could be either an aldehyde or a ketone.

Negative Tollen's test: Compound 'A' does not give a positive Tollen's test, which suggests it is not an aldehyde.

Reaction with sodium hypochlorite (${NaClO}$): Compound 'A' reacts with sodium hypochlorite to give chloroform (${CHCl_3}$) and compound 'B'.

Based on the information provided, compound 'A' has a molecular formula of ${C_5H_{10}O}$ and contains a carbonyl group. One possible structure for compound 'A' is the ketone "2-pentanone" (${CH_3COCH_2CH_2CH_3}$).

Now, let's consider the formation of compound 'B' upon treatment with sodium hypochlorite:

${CH_3COCH_2CH_2CH_3}$ (compound 'A') + ${NaClO}\rightarrow{CHCl_3}$ → CHCl3 + compound 'B'

The reaction between 2-pentanone (compound 'A') and sodium hypochlorite yields chloroform (${CHCl_3}$) and compound 'B'. Given the options provided, "Sodium propanoate," "Sodium butanoate," "Sodium acetate," and "n-Butane," the most likely choice for compound 'B' would be "Sodium acetate" (${CH_3COONa}$).

So, compound 'B' is likely to be "Sodium acetate" (${CH_3COONa}$) based on the given information.