Question

Here, in which case can the calculated standard reaction enthaply `(Delta_(1) H^(@))` be identified as the standard molar enthalpy of formation for methanol `(Delta_(g) H_(CH_(3) OH^(2)))`?
A. `CH_(4) (g) + (1)/(2) O_(2) (g) rarr CH_(3) OH (g)`
B. `C_("diamond") + (1)/(2) O_(2) (g) rarr 2 H_(2) (g) + CH_(3) OH (l)`
C. `CO (g) + 2 H_(2) (g) rarr CH_(3) OH (l)`
D. `C_("graphite") + (1)/(2) O_(2) rarr 2H_(2) (g) + CH_(3) OH(l)`

Answer 1

Correct Answer - D
The standard enthalpy of formation of a substance, denoted by `Delta_(f) H^(@)`, the the enthaply change for the formation of one mole of the substance in its standard state from its constiuent elements in their standard states. Thus, `Delta_(f) H^(@)` refers to specific reaction.