If the concentration of a reactant in a mixture is doubled and the reaction rate increases by a factor of eight, the reaction order with respect to that reactant is

Answer: Three

When the reactant concentration is increased, generally the reaction rate will be increased too. But the magnitude of the increase can differ in various reaction. In this case, 2x concentration will result in 8x reaction rate. The order will be:

2^x = 8

2^x = 2^3

x=3