Diborane is a potential rocket fuel which undergoes combustion according to the equation ${\text{B}}_{\text{2}}{\text{H}}_{\text{6(g)}}{\text{ +3O}}_{\text{2(g)}}\stackrel{}{\to }{\text{ B}}_{\text{2}}{\text{O}}_{\text{3(g)}}{\text{ + 3H}}_{\text{2}}{\text{O}}_{\text{(g)}}$. Calculate the enthalpy change for the combustion of diborane.

Given:

(i) ${\text{2B}}_{\text{(s)}}\text{+}\frac{3}{2}{\text{O}}_{\text{2(g)}}\stackrel{}{\to }{\text{B}}_{\text{2}}{\text{O}}_{\text{3(g)}}{\text{; ∆H =-1273 kJ mol}}^{\text{-1}}$

(ii) ${\text{H}}_{\text{2(g)}}\text{+}\frac{1}{2}{\text{O}}_{\text{2(g)}}\stackrel{}{\to }{\text{H}}_{\text{2}}{\text{O}}_{\text{(l)}}{\text{; ∆H =-286 kJ mol}}^{\text{-1}}$

(iii) ${\text{H}}_{\text{2}}{\text{O}}_{\text{(l)}}\stackrel{}{\to }{\text{H}}_{\text{2}}{\text{O}}_{\text{(g)}}{\text{; ∆H = 44 kJ mol}}^{\text{-1}}$

(iv) ${\text{2B}}_{\text{(s)}}{\text{+3H}}_{\text{2(g)}}\stackrel{}{\to }{\text{B}}_{\text{2}}{\text{H}}_{\text{6(g)}}{\text{; ∆H = 36 kJ mol}}^{\text{-1}}$