When two moles of liquid A are mixed with two moles of liquid B at 300 K, the excess molar Gibbs energy of the solution is -1.5 kJ mol⁻¹. The corresponding value of Gibbs energy of mixing (in kJ) is closest to (R=8.3 J K⁻¹ mol⁻¹)

Q85 · CSIR-NET Chemistry, June 2019

Paper: CSIR-NET June 2019 · Subject: Physical Chemistry · Chapter: Thermodynamics · Topic: Free Energy Equilibria · Marks: 2 · Difficulty: Medium

When two moles of liquid A are mixed with two moles of liquid B at 300 K , the excess molar Gibbs energy of the solution is $-1.5 \mathrm{kJ} \mathrm{mol}^{-1}$. The corresponding value of Gibbs energy of mixing (in kJ) is closest to $\left(\mathrm{R}=8.3 \mathrm{J} \mathrm{K}^{-1} \mathrm{mol}^{-1}\right)$

(a)-12.9

(b)-6.0

(c)-1.5

(d)-0.9

Answer

Answer: A ✓ checked by 4AB · confidence high

Explanation

ΔG_mix = nRT Σx_i ln x_i + nG^E = 4 × 8.3 × 300 × ln 0.5 + 4 × (−1500) = −6.9 − 6.0 = −12.9 kJ.

Study loop for Thermodynamics

1. Practise the PYQsPrevious-year questions, with answers

· Browse this chapter in the app