Determine C-C and C-H bond enthalpy (in `kJ//mol`) Given : `Delta_(f)H^(@)(C_(2)H_(6),g)=-85kJ//mol," "Delta_(f)H^(@)(C_(3)H_(8),g)=-104kJ//mol` `Delta_("sub")H^(@)(C,s)=718kJ//mol," "B.E.(H-H)=436kJ//mol`
A
414345
B
345414
C
`287404.5`
D
None of these
Text Solution
Verified by Experts
The correct Answer is:
B
`2 C(s)+3H_(2)(g)rarrC_(2)H_(6)(g)` `Delta_(f)H^(@)=[(2xxDelta_("sub")H(C,s)),(3xxB.E.(H-H))]` `-[(B.E.(C-C)),(+6xxB.E.(C-H))]` `-85 = 2xx718 + 3 xx 436 - (x+6y)` `x + 6y = 2829" ...(1)"` Similarly, for `C_(3)H_(8)(g)` `2x+8y= 4002 " ...(2)"` from Eqs. (1) and (2) x = 345 kJ/mol, y = 414 kJ/mol
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