Rate = k [A]x[B]y When concentration of B is doubled keeping the concentration of A constant, the rate of formation of C increases by a factor of four. This indicates that the rate of reaction depends upon the square of concentration of B. When concentration of A is doubled, the rate of formation of C also doubles from the initial value .This shows that the ratedepends on first power of concentration of A. Hence Rate = Rate = k [A][B]2