Question

If enthalpies of methane and ethane are respectively 320 and 360 calories. Then bond energy of C= C bond is ​

Answer 1

Given:

Enthalpy of methane = 320 cal

Enthalpy of ethane = 360 cal

To find:

The bond energy of C= C bond

Solution:

• We know that there are 4C - H bonds in methane (CH₄).

• Therefore Energy of C - H bond ( E (C-H) ) = 320 / 4 = 80 cal

• Also, in ethane ( C₂H₆) there is 1C - C bond and 6C - H bonds.

• Thus, E (C-C) + 6 E (C-H) = 360

                      E (C-C) + 6 x 80 = 360

                                     E (C-C) = 120 cal

• Thus the bond energy of the C=C bond will be 120 cal.