With the help of thermochemical equations given below, determine `Delta_(r )H^(Θ)` at `298 K` for the following reaction:
`C("graphite")+2H_(2)(g) rarr CH_(4)(g),Delta_(r )H^(Θ) = ?`
`C("graphite")+O_(2)(g) rarr CO_(2)(g),
Delta_(r )H^(Θ) = -393.5 kJ mol^(-1)` ...(1)
`H_(2)(g) +1//2O_(2)(g) rarr H_(2)O(l)`,
`Delta_(r )H^(Θ) = -285.8 kJ mol^(-1)` ...(2)
`CO_2(2)(g)+2H_(2)O(l) rarr CH_(4)(g)+2O_(2)(g)`,
`Delta_(r )H^(Θ) = +890.3 kJ mol^(-1)` ...(3)

Options

A. `+ 78.8kJ mol^(-1)`
B. `+144.0kJ mol^(-1)`
C. `- 74.8kJ mol^(-1)`
D. `-144.0kJ mol^(-1)`

Answer

c