On charging the lead storage battery, the oxidation state of lead changes from $x_1$ to $y_1$ at the anode and from $x_2$ to $y_2$ at the cathode. The values of $x_1, y_1, x_2, y_2$ are respectively :

Aldol condensation is a popular and classical method to prepare $\alpha, \beta$-unsaturated carbonyl compounds. This reaction can be both intermolecular and intramolecular. Predict which one of the following is not a product of intramolecular aldol condensation?

Benzene is treated with oleum to produce compound $(\mathrm{X})$ which when further heated with molten sodium hydroxide followed by acidification produces compound $(\mathrm{Y})$. The compound Y is treated with zinc metal to produce compound $(Z)$. Identify the structure of compound $(Z)$ from the following option.

One mole of an ideal gas expands isothermally and reversibly from $10 \mathrm{dm}^3$ to $20 \mathrm{dm}^3$ at 300 K . $\Delta \mathrm{U}, \mathrm{q}$ and work done in the process respectively are

Given: $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$

$\ln 10=2.3$

$\log 2=0.30$

$$\log 3=0.48$$