The change in enthalpy when the constituent elements of a compound in their standard state i.e. pressure is 1 atm and temperature is 298 K forms one mole of compound in its normal state is known as heat of formation of compound.
The symbol for change in heat of formation is \(\Delta H_f\).
Every free element in its standard state has value of \(\Delta H_f = 0\).
Thus, from the given options only \(F_2(g)\) is present in its standard state so, \(\Delta H_f\) for \(F_2(g)\) is 0.
Hence, \(F_2(g)\) will have \(\Delta H_f = 0\).
