Introduction: average rate and instantaneous rate

Explanation

Average rate of chemical reaction.
It may be defined as the change in concentration of a reaction or product of a chemical in a given interval of time.
Average rate of reaction `= ("Change in concentration of reactants or products")/("Time interval")`
Instantaneous rate of reaction
It may be defined as the rate of a reaction of a particular instant. Instantaneous reaction rate `(d[I_(2)])/(dt)` where, `d(l_(2))` = small change in concentration.
d + = small change in time.