**Answer the following in brief.**

How instantaneous rate of reaction is determined?

#### Solution

i. To determine the instantaneous rate of a reaction the progress of a reaction is followed by measuring the concentrations of a reactant or product for different time intervals.

ii. The concentration of a reactant or a product is plotted against time.

iii. A tangent drawn to the curve at time t_{1} gives the rate of the reaction. The slope thus obtained gives the instantaneous rate of the reaction at time t_{1}.

**Determination of instantaneous rate**

iv. Mathematically the instantaneous rate is expressed by replacing Δ by derivative dc/dt in the expression of the average rate.

Instantaneous rate = `("d"["C"])/"dt"`

v. For a reaction A → B

Instantaneous rate of consumption of A at time t = `-("d"["A"])/"dt"`

Instantaneous rate of the formation of B at time t = `("d"["B"])/"dt"`

Therefore, instantaneous rate of the reaction at time t = `-("d"["A"])/"dt"` = `("d"["B"])/"dt"`