Question

The ratio of number of oxygen atoms to bromine atoms in the product $Q$ is ___ $\times 10^{-1}$.

Answer 1

The initial compound with $\text{OC}_2\text{H}_5$ undergoes nitration to introduce a $\text{NO}_2$ group, yielding intermediate $P$.

$\text{OC}_2\text{H}_5 \xrightarrow{\text{HNO}_3, \text{H}_2\text{SO}_4} \text{OC}_2\text{H}_5\text{NO}_2$

Bromination of $P$ in the presence of Fe introduces two bromine atoms on the aromatic ring, resulting in product $Q$.

$\text{OC}_2\text{H}_5\text{NO}_2 \xrightarrow{\text{2 Br}_2, \text{Fe}} \text{Br-OC}_2\text{H}_5\text{NO}_2\text{Br}$

Count the number of oxygen and bromine atoms in product $Q$:

• Oxygen atoms: 3 (one from $\text{OC}_2\text{H}_5$ and two from $\text{NO}_2$)
• Bromine atoms: 2

The ratio of oxygen to bromine atoms in $Q$ is:

$\frac{3}{2} \times 10^{-1} = 15 \times 10^{-1}$

Answer: 15