In which one of the following reactions does the heat change represent the heat of formation of water?

Options

A. `2H_(2)+O_(2)to2H_(2)O,""""" DeltaH=-116kcal`
B. `H_(2)+(1)/(2)O_(2)toH_(2)O,"""""DeltaH=-58kcal`
C. `H^(+)+OH^(-)toH_(2)O(l),"""""DeltaH=-13.7kcal`
D. `C_(2)H_(2)+2(1)/(2)O_(2)to2CO_(2)+H_(2)O,"""""DeltaH+-30kcal`

Answer

B

Explanation

Heat of formation repesents the change in enthalpy in the standard state, when one whole of a compound is produced from its intergal elements. `therefore` In the reaction ,`H_(2)+(1)/(2)O_(2)toH_(2)O,DeltaH=-58kcal`,
Heat change represents the heat of formation of water.