Two reactions involving ammonium chloride are shown below

CHEMISTRY · Single correct · A Level · Chemistry · Thermodynamics · Thermodynamics

Problem

Two reactions involving ammonium chloride are shown below. I.

\text{NH}_4\text{Cl}(s)\rightarrow \text{NH}_3(g)+\text{HCl}(g)

II.

\text{NH}_4\text{Cl}(aq)\rightarrow \text{NH}_3(aq)+\text{HCl}(aq)

Which statement correctly compares the standard entropy changes,

\Delta S^{\circ}

, for the two reactions at 298 K? (a)

\Delta S^{\circ}

for reaction II is more positive because dissolving a solid into solution always increases entropy. (b) The two reactions have identical

\Delta S^{\circ}

values because each produces the same total number of moles of products. (c)

\Delta S^{\circ}

for reaction I is more positive because gaseous products are formed. (d)

\Delta S^{\circ}

for reaction II is more positive because the reaction generates additional ions, increasing randomness.