Question

Consider the following reaction of benzene. the percentage of oxygen is _______ %. (Nearest integer)

Hint:

In calculation-based organic problems, estimate percentages for simple final products ($R-OH, R-COOH$) to check for viability.

Answer 1

Correct Answer: 17

Benzene undergoes Friedel–Crafts acylation followed by alkaline hydrolysis, leading to the formation of an aromatic carboxylic acid. The final product $(Q)$ is phenylacetic acid. \[ Q = \mathrm{C_6H_5CH_2COOH} \] Molecular formula of $Q$: \[ \mathrm{C_8H_8O_2} \] Molar mass of $Q$: \[ = (8 \times 12) + (8 \times 1) + (2 \times 16) = 96 + 8 + 32 = 136 \] Mass of oxygen present: \[ = 2 \times 16 = 32 \] Percentage of oxygen: \[ \%\,\text{Oxygen} = \frac{32}{136} \times 100 = 23.52\% \] Nearest integer: \[ \boxed{23\%} \] \[ \therefore \text{Percentage of oxygen in the product is } 23\%. \]