Question

First ionisation energy of carbon is higher than boron but the reverse is true for second ionisation energy why

Answer 1

first ionisation energy of carbon is higher than boron because large energy is needed as it is 2p orbital is close to nucleus but after losing its electron it become unstable and hence its second ionisation energy is less
in case of B there is only one electron in 2p orbital and it loses it quickly. But it becomes difficult to loose its 2s orbital electron and hence second ionisation energy is more for carbon