If at 298 K the bond enèrgies of `C-H, C-C, C=C and H - H` are respectively 414, 347, 615, and 435 kJ `mol^(-1)` the value ofenthalpy change for the reaction,
`H_(2) C = CH _(2) (g) + H _(2) (g) to H _(3) C - CH _(3) (g) at 298K` will be,

Options

A. `+250 kJ`
B. `-250 kJ`
C. ` +125 kJ`
D. `-125 kJ`

Explanation

`Delta H (sum E. B` of the reactants `- sum B.E` of the products )
`= [ 615 + ( 4 xx 414 ) + 435]-[347 + (414 xx 6)]= 2706 - 2831=- 12 kJ `