Question

`H_(2)(g)+(1)/(2)O_(2)(g)rarrH_(2)O(l)`,
`DeltaH " at "298 K=-285.8 kJ`
The molar enthalpy of vaporization of water at 1 atm and `25^(@)C` is 44 kJ. The standard enthalpy of formation of 1 mole of water vapour at `25^(@)C` is
A. `-241.8` kJ
B. 241.8 kJ
C. 329.8 kJ
D. `-329.8` kJ

Answer 1

Correct Answer - A
`H_(2)+(1)/(2)O_(2)rarrH_(2)O_((l)),DeltaH=-285.8 kJ`
`H_(2)O_((l))rarrH_(2)O_((g)),DeltaH=44 kg`
`therefore H_(2)+(1)/(2)O_(2)rarrH_(2)O_((g)),DeltaH^(@)=-241.8 kJ`.