The enthalpy of formation for `C_(2)H_(4)(g)`, `CO_(2)(g)` and `H_(2)O(l)` at `25^(@)C` and `1` atm. Pressure be `52`, `-394` and `-286 kJ mol^(-1)` respectively. The enthalpy of combustion of `C_(2)H_(4)(g)` will be

Options

A. `+1412 kJ cdot mol^(-1)`
B. `+14.12 kJ cdot mol^(-1)`
C. `-1412 kJ cdot mol^(-1)`
D. `-14.12 kJ cdot mol^(-1)`

Answer

C

Explanation

`C_(2)H_(4(g))+3O_(2(g)) rarr 2CO_(2(g)) + 2H_(2)O_((l))`
`Delta H_("reaction") =[2xx Delta_(f) H^(0) (CO_(2))+2xxDelta fH^(0) (H_(2)O)]- [Delta _(f) H^(0) (C_(2) H_(4))+3xx Delta _(f) H^(0) (O_(2))]`