Chemical Thermodynamics Question 376
Question: The enthalpy of neutralisation of $ NH_4OH $ and $ CH_3COOH $ is $ -10.5kcalmo{{l}^{-1}} $ and enthalpy of neutralisation of $ CH_3COOH $ with strong base is $ -12.5,kcalmo{{l}^{-1}} $ . The enthalpy of ionisation of $ NH_4OH $ will be
Options:
A) $ 3.2kcalmo{{l}^{-1}} $
B) $ 2.0kcalmo{{l}^{-1}} $
C) $ 3.0kcalmo{{l}^{-1}} $
D) $ 4.0kcalmo{{l}^{-1}} $
Show Answer
Answer:
Correct Answer: B
Solution:
- $ {\Delta_{neu}}H $ for strong base and strong acid $ =-13.7kcal,e{{q}^{-1}} $
$ \Delta H_{ion}(CH_3COOH) $
$ =-12.5-( -13.7 )=1.2kcalmo{{l}^{-1}} $
$ \Delta H_{ion}(NH_4OH) $
$ =-10.5-(-13.7)-\Delta H_{ion}(CH_3COOH) $
$ =13.7-10.5-1.2 $
$ =2kcal,mo{{l}^{-1}} $
