Answer:
SeCl₆ + O₂ → SeO₂ + 3Cl₂
Explanation:
Unbalanced:
SeCl₆ + O₂ → SeO₂ + Cl₂
Count the atoms.
On the left side, we have 1 Se atom, 6 Cl atoms, and 2 O atoms.
On the right side, we have 1 Se atom, 2 O atoms, and 2 Cl atoms.
So everything is balanced except for Cl. To balance, we put a 3 coefficient in front of Cl₂.
SeCl₆ + O₂ → SeO₂ + 3Cl₂
