The correct options are
A ΔrH∘ for the reaction H2O(g)→2H(g)+O(g) is 925.5 kJ/mol
D Enthalpy of formation of H(g) is +218 kJ/mol
A. H2O→2H+O ΔH0r=242kJ/mol ......(1)
H2→2H ΔH0r=436kJ/mol ......(2)
12→O ΔH0r=4952=247.5kJ/mol ......(3)
Add reactions (1) to (3)
H2O→=2H+O
ΔH0r=242+436+247.5=925.5kJ/mol
Thus, the option A is correct.
H2(g)→2H(g)ΔH0r=436kJ/mol......(1)
The expression for the enthalpy of formation of H(g) is
12H2(g)→H(g)
It is obtained by dividing equation (1) with 2.
Enthalpy of formation of H(g) is 4362=218kJ/mol
Thus, the option D is correct.