Question

If the binding energy of electron in hydrogen atom is 13.6ev, the energy required to remove electron from first excited state of li

Answer 1

If the binding energy of electron in hydrogen atom is 13.6ev, the energy required to remove electron from first excited state of Li⁺ is given as 30.6 eV.

The negative value is normally assigned to this energy of hydrogen and it means that the system losses 13.6eV of energy. Or more importantly if you want to get that electron from the ground state back to infinity you need to supply 13.6eV of energy and this is the Ionization energy.