Paper: CSIR-NET December 2019 · Subject: Physical Chemistry · Chapter: Thermodynamics · Topic: Laws State Functions · Marks: 2 · Difficulty: Hard
The excess molar entropy of mixing of liquid A with liquid B is $-R\ln 2$. The experimentally observed change in entropy upon mixing 1.0 mol of liquid A with 1.0 mol of liquid B is
(a)$-2R\ln 2$
(b)$+4R\ln 2$
(c)0
(d)$+R\ln 2$
Answer
Answer: C ✓ checked by 4AB · confidence medium
Explanation
Ideal mixing of 1 + 1 mol: ΔS = 2R ln 2; the excess molar entropy −R ln 2 for 2 mol of mixture is −2R ln 2; total ΔS = 0 (c).