Question

Observe the following reaction

$X \xrightarrow{NH_2OH/HCl} Y \xrightarrow{H_2SO_4} Z \xrightarrow[(ii)H^+]{(i)NaOH/Boil} H_2N-CH_2-CH_2-CH_2-COOH$

If the molar mass of X is M × 10. Then the value of M is:

Answer 1

7

Answer 2

The given reaction sequence involves the conversion of a cyclic ketone (X) to a cyclic amide (Z) via a Beckmann rearrangement. The final product is 4-aminobutanoic acid, which is obtained by the hydrolysis of Z. This suggests that Z is a cyclic amide (lactam).

The reaction $Y \xrightarrow{H_2SO_4} Z$ is a Beckmann rearrangement, where a cyclic ketone oxime (Y) is converted into a lactam (Z). The lactam Z is a 5-membered ring, which means it is formed from a 4-membered cyclic ketone oxime. Therefore, X is cyclobutanone ($C_4H_6O$).

The molar mass of cyclobutanone is calculated as follows: $4 \times 12 + 6 \times 1 + 1 \times 16 = 48 + 6 + 16 = 70 \text{ g/mol}$

Given that the molar mass of X is $M \times 10$, we have: $70 = M \times 10$ $M = 70 / 10 = 7$

Therefore, the value of M is 7.