Which of the following reaction corresponds with the definition of standard enthalpy of combustion?

Options

A. `CH_(4) (g) + 2 O_(2) (g) rarr CO_(2) (g) + 2 H_(2) O (g)`
B. `2 CH_(4) (g) + 4 O_(2) (g) rarr 2 CO_(2) (g) + 4 H_(2) O (l)`
C. `2 CH_(4) (g) rarr 2 CO_(2) (g) + 4 H_(2) O (g)`
D. `CH_(4) (g) + 2O_(2) (g) rarr CO_(2)(g) + 2H_(2) O (l)`

Answer

D

Explanation

`Delta_(c ) H^(@)` is the enthalpy change (amount of heat released) when one mole of the substance under standard thermodynamic conditions `(268 K`, 1 bar pressure) is completely burnt in excess of oxygen to form products under stantard thermodynamic conditions.