Diborane is a potential rocket fuel which undergoes combustion according to the reaction,
`B_(2)H_(6)(g)+3O_(2)(g)toB_(2)O_(3)(s)+3H_(2)O(g)`
from the following data, the enthalpy change for the combustion of diborane will be :
`2B(s)+(3)/(2)O_(2)(g)toB_(2)O_(3)(s)," "DeltaH=-1273 " kJ"`
`H_(2)(g)+(1)/(2)O_(2)(g)toH_(2)O(l)," "DeltaH=-286 " kJ"`
`H_(2)O(l)toH_(2)O(g)," "DeltaH=44" kJ"`
`2B(s)+3H_(2)(g)toB_(2)H_(6)(g)," "DeltaH=46" kJ"`

Explanation

The required equation,
`B_(2)H_(6)(g)+3O_(2)(g)toB_(2)O_(3)(s)+3H_(2)O(g)`
can be obtained from eq.(i)`+3xxeq.(ii)+3eq.(iii)-eq.(iv)`
`=1273-858+132-36`
`=-2035kJ" "mol^(-1)`
i.e., Enthalpy of combustion of diborane is -2035kJ `mol^(-1)`.