In a second-order reaction (one that is second order in one reactant), cutting in half the concentration of that reactant will h
ave what effect on the reaction rate? A) The reaction rate will remain the same.
B) The reaction rate will double.
C) The reaction rate will decrease by a factor of two.
D) The reaction rate will increase by a factor of four.
E) The reaction rate will decrease by a factor of four.
Answer: D) The reaction rate will increase by a factor of four.
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
A second order reaction varies with the square of the concentration of the reactant. Therefore, halving the concentration will reduce the rate of reaction by a factor of 4. The answer is E.