Embibe Experts Solutions for Chapter: Thermodynamics, Exercise 1: CG PET 2018

The standard enthalpy of vaporisation ${\mathrm{\Delta }}_{\mathrm{vap} }\mathrm{H}°$, for water at $100°\mathrm{C}$ is $40.66 \mathrm{kJ}{ \mathrm{mol}}^{-1}$. The internal energy of vaporisation of water at $100°\mathrm{C}$ (in ${\mathrm{kJmol}}^{-1}$ ) is (assume water vapour to behave like an ideal gas)

Consider the following reaction: $\mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)⟶{\mathrm{CaCO}}_3\left(\mathrm{s}\right)$. The reaction is spontaneous at low temperature because

Which is the most thermodynamically stable form of carbon?

The heat of neutralisation of hydrogen cyanide $\left(\mathrm{HCN}\right)$ is $-2.9 \mathrm{kcal} {\mathrm{mol}}^{-1}$. This shows that heat of dissociation of $\mathrm{HCN}$ is

Equal volume of $1 \mathrm{M} \mathrm{HCl}$ and $1 \mathrm{M} {\mathrm{H}}_2{\mathrm{SO}}_4$ are neutralised by dil. $\mathrm{NaOH}$ solution separately. If $\mathrm{X} \mathrm{Kcal}$ and $\mathrm{Y} \mathrm{Kcal}$ of heat are liberated respectively, then which of the following relation is correct?

Which expression has no physical significance?

For a chemical reaction, $∆\mathrm{G}$ is always less than zero $\left(\mathrm{\Delta G}<0\right)$ if