The correct difference between first- and
second-order reaction is that
(1) the rate of a first-order reaction does not depend
on reactant concentration; the rate of a second-
order reaction does depend on reactant
concentrations.
(2) the half-life of a first-order reaction does not
depend on ``[A]_0``; the half-life of a second-order
reaction does depend on ``[A]_0``
(3) a first-order reaction can be catalyzed;
a second-order reaction cannot be catalyzed.
(4) the rate of a first-order reaction does depend
on reactant concentrations; the rate of a
second-order reaction does not depend on
reactant concentrations