



Step 1: When sec-butylcyclohexane reacts with bromine in the presence of sunlight, a free radical substitution reaction occurs.
Step 2: In this reaction, the bromine atom will substitute one of the hydrogen atoms at the benzylic position of sec-butylcyclohexane. The benzylic hydrogen is the most reactive in this case due to the stability of the resulting free radical formed by the abstraction of the hydrogen atom.
Step 3: Therefore, the major product will have a bromine atom attached to the carbon atom adjacent to the cyclohexane ring, which is the sec-butyl position.
Identify A in the following reaction. 
A substance 'X' (1.5 g) dissolved in 150 g of a solvent 'Y' (molar mass = 300 g mol$^{-1}$) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent 'Y' is $____________ \(\times 10^{-2}\). (nearest integer)
[Given : $K_{b}$ of the solvent = 5.0 K kg mol$^{-1}$]
Assume the solution to be dilute and no association or dissociation of X takes place in solution.
Inductance of a coil with \(10^4\) turns is \(10\,\text{mH}\) and it is connected to a DC source of \(10\,\text{V}\) with internal resistance \(10\,\Omega\). The energy density in the inductor when the current reaches \( \left(\frac{1}{e}\right) \) of its maximum value is \[ \alpha \pi \times \frac{1}{e^2}\ \text{J m}^{-3}. \] The value of \( \alpha \) is _________.
\[ (\mu_0 = 4\pi \times 10^{-7}\ \text{TmA}^{-1}) \]