Complex A has a composition of H_12 O_6 Cl_3Cr. If the complex on treatment with conc. H_2 SO_4 loses 13.5% of its original mass, the correct…

It is noticed that $\mathrm{Pb}^{2+}$ is more stable than $\mathrm{Pb}^{4+}$ but $\mathrm{Sn}^{2+}$ is less stable than $\mathrm{Sn}^{4+}$. Observe the following reactions. $\mathrm{PbO}_{2}+\mathrm{Pb} \rightarrow 2 \mathrm{PbO} ; \Delta_{\mathrm{r}} \mathrm{G}^{\circ}(1)$ $\mathrm{SnO}_{2}+\mathrm{Sn} \rightarrow 2 \mathrm{SnO} ; \Delta_{\mathrm{r}} \mathrm{G}^{\circ}(2)$ Identify the correct set from the following

In a period, the first ionisation enthalpy of the element at extreme left and the negative electron gain enthalpy of the extreme right element, except noble gases, are respectively.

First and second ionization enthalpies of lithium are $520$ kJ mol$^{-1}$ and $7297$ kJ mol$^{-1}$ respectively. Energy required to convert $3.5$ mg lithium (g) into $\text{Li}^{2+}$(g) $[\text{Li(g)} \rightarrow \text{Li}^{2+}\text{(g)}]$ is _______ kJ mol$^{-1}$. (nearest integer) [Molar mass of Li $= 7$ g mol$^{-1}$]

Which of the following elements has the highest electronegativity?

On heating a mixture of common salt and $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ in equal amount along with concentrated $\mathrm{H}_{2} \mathrm{SO}_{4}$ in a test tube, a gas is evolved. Formula of the gas evolved and oxidation state of the central metal atom in the gas respectively are: