Which of the following reactions defines `DeltaH_(f)^(@)` ?

Options

A. `C("diamond") + O_(2)(g) to CO_(2)(g)`
B. `1/2H_(2)(g) + 1/2F_(2)(g) to HF(g)`
C. `H_(4)P_(2)O_(7) + H_(2)O to 2H_(3)PO_(4)`
D. `SO_(2) (g) + 1/2O_(2)(g) to SO_(3)(g)`

Answer

B

Explanation

Standard Gibbs's energy of formation `(DeltaG_(f)^(@))` of a substance is defined as the Gibb's energy change when mole of the substance is formed from its elements in their standard states. The following reaction define `DeltaG_(f)^(@)`
`1/2 H_(2)(g) + 1/2F_(2)(g) to HF(g)`