The reaction

BrOˉ + 3SO₃²ˉ → Brˉ +3SO₄²ˉ
Has the rate, Rate = k[BrOˉ] [SO₃²ˉ]
What is the order of the reaction with respect to each reactant?

The order of the reaction with respect to BrOˉ is 1, and the order with respect to SO₃²ˉ is also 1. This is because the rate law shows that the rate of the reaction is directly proportional to the concentration of BrOˉ and SO₃²ˉ.