Chemical Thermodynamics Question 428
If enthalpies of formation of methane and ethane are respectively 320 and 360 calories then the bond energy of $ C-C $ bond is [UPSEAT 2003]
Options:
A) 80 calories
B) 40 calories
C) 60 calories
D) 120 calories
Show Answer
Answer:
Correct Answer: B
Solution:
$ CH_4\to C+4H,\Delta H=+320 $
$ {E_{C-H}}=90,cal $
$ C_2H_6\to 2C+3H_2,,\Delta H=360 $
$ \therefore 360={E_{C-C}}+6{E_{C-H}} $
$ \therefore {E_{C-C}}=360-320=40cal $ .
BETA
