# How to find the order of a reaction when rate constant is not given?

When  rate constant is not given then we can find the order of reaction through graphical method.By plotting a graph of values obtained of concentration vs time.
Order of a reaction is always determined experimentally on the basis of dependence of rate of reaction on concentration of reacting species. In order to determine this dependence, we have to find how the concentration of various reacting species vary during the reaction. For example, a known volume of the reaction mixture may be taken out during different time intervals, and then the concentration of reactant can be determined by volumetric titration or any other analytical technique. We can also determine this by change in the conductivities or the specific rotation.

The rate law equation for respective order of reaction are :

Graphs obtained are  as follows :

• 2

If it is given that Rate is proportional to [A]a[B]b , then order = a+b.

• -2

the sum of the powers of the concentation of the reactants in the slowest determing step....

• 2

if rate law is not given, if a b are not known, how to determine the order

• 1

You mean - the questions having tabular coloumns???

• -1

yes

• 0

Consider rate = k [A]a [B]b.

From the tabular coloumn, substitute values into this equation and find a,b,k.

• 2
What are you looking for?