In the reaction a + b c, doubling the concentration of a doubles the reaction rate and doubling the concentration of b doubles the reaction rate. which statement best describes this reaction? it is a second-order reaction in a and a second-order reaction in b. it is a first-order reaction in a and a second-order reaction in b. it is a first-order reaction in a and a first-order reaction in b. it is a second-order reaction in a and a first-order reaction in b. it is a zero-order reaction with respect to both reactants.