For the equilibrium $\mathrm{H}_2 \mathrm{O}_{(l)} \rightleftharpoons \mathrm{H}_2…

For the equilibrium $\mathrm{H}_2 \mathrm{O}_{(l)} \rightleftharpoons \mathrm{H}_2 \mathrm{O}_{(\mathrm{g})}$ at 1 atm and $298 \mathrm{~K}$,
  1. standard free energy change is equal to zero $\left(\Delta G^{\circ}=0\right)$
  2. free energy change is less than zero $(\Delta G < 0)$
  3. standard free energy change is less than zero $\left(\Delta G^{\circ} < 0\right)$
  4. standard free energy change is greater than zero $\left(\Delta G^{\circ} > 0\right)$.

Solution

$\mathrm{H}_2 \mathrm{O}_{(l)} \rightleftharpoons \mathrm{H}_2 \mathrm{O}_{(g)}$ This is a spontaneous process at standard conditions thus, the standard free energy change must be less then zero, i.e. $\Delta G^{\circ} < 0$.

Asked in: NEET 2010 (Mains)

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