Step 1: Meaning of hybridization.
Hybridization involves mixing of atomic orbitals of similar energy to form hybrid orbitals.
Step 2: Processes involved.
During hybridization, excitation of electrons and recasting of orbitals may occur, leading to formation of \( \sigma \)-bonds.
Step 3: Identifying the incorrect process.
Loss and gain of electrons is related to redox reactions or ionic bond formation, not hybridization.
Step 4: Conclusion.
Hence, loss and gain of electron is NOT found in hybridization.