How do the rates of the forward and reverse reactions compare at a state of dynamic chemical equilibrium?

1 Answer
May 4, 2018

They are equal, and NONzero.


At dynamic chemical equilibrium, the rates of the forward and reverse reactions are equal to each other, i.e.

aA+bBk1 cC+dD
k1

For this, assuming the equilibrium consists of elementary reactions, the forward rate law and reverse rate law are:

r1(t)=k1[A]a[B]b
r1(t)=k1[C]c[D]d

At equilibrium, r1(t)=r1(t), so:

k1[A]a[B]b=k1[C]c[D]d

From this, we obtain:

Kk1k1=[C]c[D]d[A]a[B]b

We know that rate constants are temperature-dependent, and thus, so is K.

It is also important to note that the rates of the forward and reverse reactions MUST be nonzero to have a dynamic chemical equilibrium.