Given :
(i) `NH_(3) (g) + 3Cl_(2)(g) rarr NCl_(3)(g)+3HCl(g)`, `Delta H_(1)`
(ii) `N_(2)(g) + 3H_(2)(g) rarr 2NH_(3)(g)` , `Delta H_(2)`
(iii) `H_(2)(g)+Cl_(2)(g) rarr2HCl(g)` , `Delta H_(3)`
Express the enthalpy of formation of `NCl_(3)(g)(Delta H_(f))` in terms of `DeltaH_(1), Delta H_(2)` and `Delta H_(3)`:

Options

A. `Delta H_(f) = Delta H_(1) - (Delta H_(2))/(2)+(3)/(2)Delta H_(3)`
B. `Delta H_(f) = Delta H_(1)+(1)/(2)Delta H_(2)-(3)/(2)Delta H_(3)`
C. `Delta H_(f) = DeltaH_(1) - (1)/(2)Delta H_(2) - (3)/(2)Delta H_(3)`
D. `Delta H_(f) = DeltaH_(1) + (1)/(2)Delta H_(2) + (3)/(2)Delta H_(3)`

Answer

B