Chemical Thermodynamics Question 272
Question: The $ \Delta H_{f}^{o} $ for $ CO_2(g),,CO(g) $ and $ H_2O(g) $ are - 393.5, -110.5 and - 241.8kJmol-1 respectively. The standard enthalpy change (in kJ) for the reaction $ CO_2(g)+H_2(g)\to $
$ CO(g)+H_2O(g) $ is [IIT JEE (Screening) 2000]
Options:
A) 524.1
B) 41.2
C) - 262.5
D) - 41.2
Show Answer
Answer:
Correct Answer: B
Solution:
$ C+O_2\to C{O_{2(g)}},,\Delta H_{f}^{o}=-393.5,kJ,mo{{l}^{-1}} $ -.(i) $ C+\frac{1}{2}O_2\to C{O_{(g)}},,\Delta H_{f}^{o}=-110.5,kJ,mo{{l}^{-1}} $ -.(ii) $ H_2+\frac{1}{2}O_2\to H_2{O_{(g)}},,\Delta H_{f}^{o} $
$ =-241.8,kJmo{{l}^{-1}} $ …(iii) By (ii) + (iii) - (i) $ C{O_{2(g)}}+{H_{2(g)}}\to C{O_{(g)}}+H_2{O_{(g)}},,\Delta H=+41.2 $ .
