During which of the following processes, does entropy decrease?
(A) Freezing of water to ice at \(0^\circ\mathrm{C}\)
(B) Freezing of water to ice at \(-10^\circ\mathrm{C}\)
(C) \(\mathrm{N_2(g)+3H_2(g)\to2NH_3(g)}\)
(D) Adsorption of CO(g) on lead surface.
(E) Dissolution of NaCl in water
Choose the correct answer from the options given below :
(A) Freezing of water to ice at \(0^\circ\mathrm{C}\)
(B) Freezing of water to ice at \(-10^\circ\mathrm{C}\)
(C) \(\mathrm{N_2(g)+3H_2(g)\to2NH_3(g)}\)
(D) Adsorption of CO(g) on lead surface.
(E) Dissolution of NaCl in water
Choose the correct answer from the options given below :
Show Hint
- (A), (C) and (E) only
- (B) and (C) only
- (A), (B), (C) and (D) only
- (A) and (E) only
The Correct Option is C
Solution and Explanation
(B) Freezing at \(-10^\circ\mathrm{C}\) (supercooled water to ice): the system becomes more ordered, \(\Delta S\lt0\).
(C) 4 mol of gas gives 2 mol of gas, so disorder decreases, \(\Delta S\lt0\).
(D) Adsorbed gas molecules are restricted on the surface, \(\Delta S\lt0\).
(E) Dissolution of NaCl in water: ions go from an ordered crystal into solution, \(\Delta S\gt0\).
So entropy decreases in (A), (B), (C) and (D) only.
Answer: (3) (A), (B), (C) and (D) only
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