The enthalpy of formation of `H_(2)O(l)` is -280.70 kJ/mol and enthalpy of neutralisation of a strong acid and strong base is -56.70 kJ/mol. What is the enthalpy of formation of `OH^(-)` ions?

Options

A. `+229.70KJ`
B. `-229.70KJ`
C. `+226.70KJ`
D. `-22.670KJ`

Answer

A

Explanation

`H^(+)(aq)+OH^(-)(aq)rarrH_(2)O(l),DeltaH=-56.07KJ`
`DeltaH=DeltaH_(f)(H_(2)O)-[Delta_(f)(H^(+))+DeltaH_(f)(OH)^(-)]`
`[:. DeltaH_(f)(H)^(+)=0]-56.07=-285.77-(0+x)`
`:. x=-285.77+56.07=-229.70KJ`