If the binding energy of the electron in a hydrogen atom is 13.6eV, the energy required to remove the electron from the first excited state of Li++ is :

We know that:
E = 13.6 * (z^2 / n^2)
For hydrogen atom, z = 1 and for first excited state n = 2.
The energy required to remove electron from the first excited state of hydrogen is:
E = 13.6 * (1^2 / 2^2) = 3.4 eV
For Li++, z = 3. For first excited state, n = 2.
The energy required to remove the electron from the first excited state of Li++ is:
E = 13.6 * (3^2 / 2^2) = 13.6 * (9 / 4) = 30.6 eV