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 \( Q \):
The ratio of oxygen to bromine atoms in \( Q \) is:
\[ \frac{3}{2} \times 10^{-1} = 15 \times 10^{-1} \]
Answer: 15
Testosterone, which is a steroidal hormone, has the following structure
The total number of asymmetric carbon atoms in testosterone is ___
If \[ \frac{dy}{dx} + 2y \sec^2 x = 2 \sec^2 x + 3 \tan x \cdot \sec^2 x \] and
and \( f(0) = \frac{5}{4} \), then the value of \[ 12 \left( y \left( \frac{\pi}{4} \right) - \frac{1}{e^2} \right) \] equals to: