Standard entropies of $X_2, Y_2$ and $XY_5$ are $70, 50$ and $110 \ J \ K^{-1} \ mol^{-1}$ respectively. The temperature in Kelvin at which the reaction $\frac{1}{2} X_2 + \frac{5}{2} Y_2 \rightarrow XY_5$ with $\Delta H = -35 \ kJ \ mol^{-1}$ will be at equilibrium is . . . . . . (Nearest integer).

Which of the following processes is associated with a decrease in entropy?

At $25\,^oC$ and $1\,atm$ pressure,mercury reacts with chlorine to form mercurous chloride: $2Hg + Cl_2 \to Hg_2Cl_2; \Delta H = -31.3\,kcal$. What is the entropy change of the reaction at $25\,^oC$?

One mole of an ideal gas at $350 \, K$ is in a $2.0 \, L$ vessel with thermally conducting walls,which are in contact with the surroundings. It undergoes isothermal expansion from $2.0 \, L$ to $3.0 \, L$ against a constant external pressure of $4 \, atm$. The change in entropy of the surroundings $(\Delta S_{surr})$ is $...... \, J \, K^{-1}$ (Nearest integer). Given: $R = 8.314 \, J \, K^{-1} \, mol^{-1}$.

The second law of thermodynamics states that in a cyclic process:

For the reaction $MgCO_3(s) \rightarrow MgO(s) + CO_2(g)$,the value of $\Delta S$ is: