The standard enthalpy of formation of `C_(7)H_(5)N_(3)O_(6)(s)` is -x `kJ*mol^(-1)` at `25^(@)C`. Write the thermochemical equation for the formation reaction of the compound.

Explanation

The constituent elements of the compound `C_(7)H_(5)N_(3)O_(6)(s)` are carbon, hydrogen, oxygen and nitrogen whose standard states at `25^(@)C are C` (graphite, s), `H_(2)(g)`, `O_(2)(g) and N_(2)(g)` respectively. Therefore, the equation representing the formation reaction of the compound should contain C (graphite, s), `H_(2)(g),O_(2)(g) and N_(2)(g)` as the sources of carbon, hydrogen, oxygen and nitrogen respectively. hence, the thermochemical equation for the formation reaction of the give compound is-
7C(graphite,s)`+(5)/(2)H_(2)(g)+3O_(2)(g)+(3)/(2)N_(2)(g)toC_(7)H_(5)N_(3)O_(6)(s),DeltaH_(f)^(0)[C_(7)H_(5)N_(2)O_(6)(s)]=-xkJ*mol^(-1)`.