Which one of the following has $\Delta S^{\circ}$ greater than zero?

• A

  $\mathrm{CaO}$$(s)+\mathrm{CO}_2$$(g) \rightleftharpoons \mathrm{CaCO}_3$$(s)$
• B

  $\mathrm{NaCl}_{(a q)} \rightleftharpoons \mathrm{NaCl}_{(s)}$
• Correct answer
  C

  $\mathrm{NaNO}_{3(s)} \rightleftharpoons \mathrm{Na}_{(a q)}^{+}+\mathrm{NO}_3^{-}{ }_{(a q)}$
• D

  $\mathrm{N}_{2(g)}+3 \mathrm{H}_{2(\mathrm{~g})} \rightleftharpoons 2 \mathrm{NH}_{3(g)}$

Hence, the correct answer is option: 'C'.