The heat of atomisation of `PH_(3)(g)` and `P_(2)H_(4)(g)` are `954 kJ mol^(-1)` and `1485 kJ mol^(-1)` respectively. The `P-P` bond energy in `kJ mol^(-1)` is

Answer

213 kJ/mol

Explanation

`PH_(3) rarr P+3H" "DeltaH=954`
`P-H` bond enthalpy `=954/3=318 kJ`
`H-underset(H)underset(|)(P)-underset(H)underset(|)(P)-H rarr 2P+4H" "DeltaH=1485`
`1485=P-P+(4xx318)`
`P-P=213" kJ mol"^(-1)`