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Amongst the chemical reactions given below, the reactions with increasing entropy are
(i) $\mathrm{H}_2 \mathrm{O}(l) \rightarrow \mathrm{H}_2 \mathrm{O}(g)$
(ii) $\mathrm{C}(s)+\mathrm{CO}_2(g) \rightarrow 2 \mathrm{CO}(g)$
(iii) $2 \mathrm{H}_2(g)+\mathrm{O}_2(g) \rightarrow 2 \mathrm{H}_2 \mathrm{O}(l)$
(iv) $\mathrm{N}_2(g)+\mathrm{O}_2(g) \rightarrow$ Mixture of $\mathrm{N}_2$ and $\mathrm{O}_2$
Options:
(i) $\mathrm{H}_2 \mathrm{O}(l) \rightarrow \mathrm{H}_2 \mathrm{O}(g)$
(ii) $\mathrm{C}(s)+\mathrm{CO}_2(g) \rightarrow 2 \mathrm{CO}(g)$
(iii) $2 \mathrm{H}_2(g)+\mathrm{O}_2(g) \rightarrow 2 \mathrm{H}_2 \mathrm{O}(l)$
(iv) $\mathrm{N}_2(g)+\mathrm{O}_2(g) \rightarrow$ Mixture of $\mathrm{N}_2$ and $\mathrm{O}_2$
Solution:
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Verified Answer
The correct answer is:
(i), (ii), (iv)
(i) $\mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightleftharpoons \mathrm{H}_2 \mathrm{O}(\mathrm{g})$ system is changed so, entropy is maximum.
(ii) $\mathrm{C}(\mathrm{s})+\mathrm{CO}_2(\mathrm{~g}) \longrightarrow 2 \mathrm{CO}(\mathrm{g})$ in this system product has more number of gaseous moles. Thus, entropy increases.
(iii) $2 \mathrm{H}_2(g)+\mathrm{O}_2(g) \longrightarrow 2 \mathrm{H}_2 \mathrm{O}(l)$ gaseous system is converted into liquid system. So, entropy decreases.
(iv) $\mathrm{N}_2(g)+\mathrm{O}_2(g) \longrightarrow$ mixture of $\mathrm{N}_2$ and $\mathrm{O}_2$ mixture of $\mathrm{N}_2$ and $\mathrm{O}_2$, on mixing total gaseous volume increases in comparison to their individual volume hence entropy increases.
(ii) $\mathrm{C}(\mathrm{s})+\mathrm{CO}_2(\mathrm{~g}) \longrightarrow 2 \mathrm{CO}(\mathrm{g})$ in this system product has more number of gaseous moles. Thus, entropy increases.
(iii) $2 \mathrm{H}_2(g)+\mathrm{O}_2(g) \longrightarrow 2 \mathrm{H}_2 \mathrm{O}(l)$ gaseous system is converted into liquid system. So, entropy decreases.
(iv) $\mathrm{N}_2(g)+\mathrm{O}_2(g) \longrightarrow$ mixture of $\mathrm{N}_2$ and $\mathrm{O}_2$ mixture of $\mathrm{N}_2$ and $\mathrm{O}_2$, on mixing total gaseous volume increases in comparison to their individual volume hence entropy increases.
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