Easy INTEGER +4 / -1 PYQ · JEE Mains 2020

For the reaction :

A($l$) $\to$ 2B(g)

$\Delta U = 2.1\,kcal,\,\Delta S = 20\,cal\,{K^{ - 1}}$ at 300 K

Hence $\Delta$G in kcal is :

Answer (integer) -2

Solution

A($l$) $\to$ 2B(g) <br><br>We know, $\Delta$H = $\Delta$U + $\Delta$n<sub>g</sub>RT <br><br>and $\Delta$G = $\Delta$H - T$\Delta$S <br><br>$\therefore$ $\Delta$G = $\Delta$U + $\Delta$n<sub>g</sub>RT - T$\Delta$S <br><br>= 2.1 + ${{2 \times 2 \times 300} \over {1000}}$ - ${{300 \times 20} \over {1000}}$ <br><br>= 2.1 + 1.2 - 6 = – 2.70 Kcal/mol

About this question

Subject: Chemistry · Chapter: Thermodynamics · Topic: Zeroth and First Law

This question is part of PrepWiser's free JEE Main question bank. 110 more solved questions on Thermodynamics are available — start with the harder ones if your accuracy is >70%.

Drill 25 more like these. Every day. Free.

PrepWiser turns these solved questions into a daily practice loop. Chapter-wise drills, full mocks, AI doubt chat. No auto-renew.

Start free →