MCQ
For the reaction, $\text{X}_2\text{O}_4(\text{l})\rightleftharpoons2\text{XO}_2(\text{g})$
$\Delta\text{U}=2.1\text{K cal}, \ \Delta\text{S}=20\text{cal K}^{-1}$ at $300K,$ Hence $\Delta\text{G}$ is : $[h = 2 \text{cal}]$
  • A
    $2.7\text{K cal}$
  • $-2.7\text{K cal}$
  • C
    $9.3\text{K cal}$
  • D
    $-9.3\text{K cal}$

Answer

Correct option: B.
$-2.7\text{K cal}$
$\Delta\text{H}=\Delta\text{U}+\Delta\text{n}\text{RT}$
$\Delta\text{H}=2100\text{cal}+2\times2\times300$
$=2100\text{cal}+1200\text{cal}=330\text{cal}$
$\Delta\text{G}=\Delta\text{H}-\text{T}\Delta\text{S}$
$=3300\text{cal}-20\times300$
$=3300\text{cal}-6000\text{cal}$
$=-2700\text{cal}=-2.7\text{K cal}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free