Above equation
can also be written as
Rate = k [A]
x  [B]
y
(3 4a)
[
]
[
] [ ]
x
y
d R
A
B
d
k
t
−
=
(3 4b)
This form of equation (3 4 b) is known as differential rate equation,
where  k is a proportionality constant called rate constant