Chemical Thermodynamics Question 99
Question: Consider the reaction : $ N_2+3H_2\to 2NH_3 $ carried out at constant temperature and pressure. If $ \Delta H $ and $ \Delta U $ are the enthalpy and internal energy changes for the reaction, which of the following expression is true [AIEEE 2005]
Options:
A) $ \Delta H=0 $
B) $ \Delta H=\Delta U $
C) $ \Delta H<\Delta U $
D) $ \Delta H>\Delta U $
Show Answer
Answer:
Correct Answer: C
Solution:
At constant P or T $ \Delta H=\Delta U+\Delta nRT $
Þ $ \Delta n=n_{p}-n_{R}=2-4=-2 $
$ \therefore $ $ \Delta H<\Delta U $ .
