Answer: the speed at which products form
Explanation:
Rate of a reaction is defined as the speed at which a chemical reaction proceeds. It is often expressed in terms of the concentration of a reactant that is consumed in a unit time or the concentration of a product that is formed in a unit of time.
For a general reaction :[tex]A\rightarrow B[/tex]
[tex]Rate=-\frac{d[A]}{dt}[/tex]
or [tex]Rate=+\frac{d[B]}{dt}[/tex]
where d[A] = change in concentration of reactant A
d[B] = change in concentration of product B
dt = time interval