Answer:
6F2 ( g ) + 2Ga2O ( aq ) → 4GaF3 + O2
F is more reactive than O, so F displaces O from Ga2O and forms GaF3.
Ga has a valency of 3, it need 3 electrons to get complete electronic configuration.
F has a valency of 1,
3 F atoms constitutes 3 electrons.
So, GaF3.
And hence, the chemical equation is balanced on both sides.
