`2Fe+(3)/(2)O_(2)rarr Fe_(2)O_(3)" "xkJ//mol e`
`2Fe+O_(2) rarr 2FeO" " ykJ //mol e`
The `DeltaH` to form one mole of `Fe_(3)O_(4)` from `Fe` and `O_(2)` is `:`

Options

A. `x/2 + y`
B. `(2x + y)/2`
C. `(2x - y)/2`
D. `(y - 2x)/2`

Answer

B

Explanation

`2Fe + 3/2 O_(2) rarr Fe_(2)O_(3) , DeltaH_(1) = x" "……(1)`
`2Fe + O_(2) rarr 2Fe_(2)O , DeltaH_(2) = y" "……(2)`
`Fe + 1/2 O_(2) rarr FeO, DeltaH_(3) = y/2" "……(3)`
Equation (1) + Equation (3)
`3Fe + 2O_(2) rarr Fe(2)O_(3) FeO " i.e. "Fe_(3)O_(4)" "....(4)`
`DeltaH = x + y/2 = (2x + y)/2`.