Chemical Thermodynamics Question 129
Question: $ \Delta E^{o} $ of combustion of isobutylene is $ -X,kJ,mo{{l}^{-1}} $ . The value of $ \Delta H^{o} $ is [DCE 2004]
Options:
A) $ =\Delta E^{o} $
B) $ >\Delta E^{o} $
C) $ =0 $
D) $ <\Delta E^{o} $
Show Answer
Answer:
Correct Answer: D
Solution:
$ {{(CH_3)}_2}C=CH_2(g)+6O_2(g)\to 4CO_2(g)+4H_2O(l) $
$ \Delta ng=4-6=-2 $ (i.e., negative) we know that $ \Delta H=\Delta E+\Delta ngRT $
$ =\Delta E-(\Delta ng)RT $ ( $ \because ,\Delta ng=-ve) $
$ \therefore \Delta H<\Delta E $
