Question
Give reason:
When Cl2 reacts with an excess of F2. ClF3 is formed and not FCl3
Solution
Chlorine has empty d-orbital and it acquires excited state at the time of bonding when an electron from 3p-orbital are promoted to 3d- orbital.
In first excited state chlorine atom can exhibit a covalency of three, hence cannot expand its octet due to the absence of empty d- orbitals in 2nd energy shell.
Hence, it cannot exhibit covalency more than 1therefore FCl3 is not possible.
