Which of the following equations indicates increase in entropy?

Which of the following equations indicates increase in entropy?
  1. $\quad \mathrm{CaO}_{(\mathrm{s})}+\mathrm{CO}_{2(\mathrm{~g})} \longrightarrow \mathrm{CaCO}_{3(\mathrm{~s})}$
  2. $\mathrm{NaCl}_{(\mathrm{aq})} \longrightarrow \mathrm{NaCl}_{(\mathrm{s})}$
  3. $\mathrm{NaNO}_{3(\mathrm{~s})} \longrightarrow \mathrm{Na}_{(\mathrm{aq})}^{+}+\mathrm{NO}_{3(\mathrm{aq})}^{-}$
  4. $\mathrm{N}_{2(\mathrm{~g})}+3 \mathrm{H}_{2(\mathrm{~g})} \longrightarrow 2 \mathrm{NH}_{3(\mathrm{~g})}$

Solution

Solid $\mathrm{NaNO}_3$ changes to two aqueous products. Aqueous phase has more randomness than solid phase and hence, entropy of the system increases.

Asked in: MHT CET 2024 (10 May Shift 1)

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