Chemical Thermodynamics Question 138
Question: For the reaction, $ {A_{(s)}}+2{B_{(g)}}\to 4{C_{(s)}}+{D_{(l)}} $ . $ \Delta H $ and $ \Delta U $ are related as — [Orissa JEE 2004]
Options:
A) $ \Delta H=\Delta U $
B) $ \Delta H=\Delta U+3RT $
C) $ \Delta H=\Delta U+RT $
D) $ \Delta H=\Delta U-3RT $
Show Answer
Answer:
Correct Answer: D
Solution:
$ A(s)+3B(g)\to 4C(s)+D(l) $
$ \Delta ng=0-3=-3 $ ; $ \Delta H=\Delta E+\Delta ngRT $
$ [\because \Delta E=\Delta U] $
$ \therefore \Delta H=\Delta U+(-3),(RT) $
$ \Delta H=\Delta U-3,(RT) $ ; $ \Delta H=\Delta U-3RT $
