Reaction rate usually has the units of mol dm−3 s−1.
Rate of reaction = decrease in the concentration of a reactant / Time interval
= increase in the concentration of a product / Time interval
As concentration is usually expressed in moles / litre and the time is taken in seconds or minutes, the unit of rate of reaction is moles litre-1 sec-1 or moles litre-1 min-1
We hope that clarifies your query.