What volume of hydrogen gas at STP would be liberated by action of 50 mL of $\mathrm{H}_2 \mathrm{SO}_4$ of $50 \%$ purity (density $=1.3 \mathrm{~g} \mathrm{~mL}^{-1}$ ) on 20 g of zinc?

Given : Molar mass of $\mathrm{H}, \mathrm{O}, \mathrm{S}, \mathrm{Zn}$ are 1, 16, 32, $65 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively.

Which of the following statement(s) is/are true ?

A. If two orbitals have the same value of ( $\mathrm{n}+l$ ), the orbital with lower value of n will have lower energy.

B. Energies of the orbitals in the same subshell increase with increase in atomic number.

C. The size of $2 \mathrm{p}_x$ orbital is less than the size of $3 \mathrm{p}_x$ orbital.

D. Among 5f, 6s, 4d, 5p and 5d orbitals, none of the orbitals have 2 radial nodes.

Choose the correct answer from the options given below :

The covalent radii of atoms $A$ and $B$ are $r_A$ and $r_B$, respectively. The covalent bond length and total length of AB molecule are respectively

Consider the following data for the reaction

$$ X_2(g)+Y_2(g) \rightleftharpoons 2 X Y(g) $$

at $600 \mathrm{~K}^{\circ}$. The $\Delta_{\mathrm{r}} \mathrm{G}^{\ominus}$ (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) for the reaction is :

$$ \begin{array}{|c|c|c|} \hline \text { Compound } & \Delta_f \mathrm{H}_{600 \mathrm{~K}}^{\ominus}\left(\mathrm{kJ} \mathrm{~mol}^{-1}\right) & \mathrm{S}^{\ominus}{ }_{600 \mathrm{~K}}\left(\mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right) \\ \hline \mathrm{XY}(\mathrm{~g}) & 42 & 200 \\ \hline \mathrm{X}_2(\mathrm{~g}) & 8 & 140 \\ \hline \mathrm{Y}_2(\mathrm{~g}) & 80 & 250 \\ \hline \end{array} $$