Yes of course reaction kinetics may be determined just by following the concentration a single specie either product or reactant in the time domain.

The rate of reaction may be determined by the amount of product formed during given time intervals, taking into account the corresponding stoichiometric factor.

Whenever the rate of reaction with respect to any reactant or product is divided by the stoichiometric numbers of that reactant or product the resulting quantity would become independent of the choice of the reactant or product and thus in this manner a single rate can be defined for a reaction: For example consider the following general reaction:

aA + bB = cC + dD

Rate of reaction (R) = -(1/a)(dCA/dt) = -(1/b)(dCB/dt) = (1/c)(dCC/dt) = (1/d)(dCD/dt)

Where the stoichiometric numbers a and b are negative (typical for reactants) and c and d are positive (typical for products)

In this manner the selection of either a reactant or a product is satisfactory for the estimation of the rate of a chemical reaction.

yes the above mentioned statement is true but how you can find out K 

aA + bB = cC + dD

Rate of reaction (R) = -(1/a)(dCA/dt) = -(1/b)(dCB/dt) = (1/c)(dCC/dt) = (1/d)(dCD/dt)

As we know rate of reaction=K[reactant] .Here product concentration is not taken in to consideration.

So how we can find out reaction rate constant k and order of the reaction?

The determination of the order of reaction and the rate constant is usually the second step in the establishment of the kinetic rate law for a reaction. If little is known in advance about the rate law of a chemical reaction, the best approach for determination of the order of reaction and the rate constant is to employ the differential method for the analysis of the kinetic data. This method is based on the following equation:

Rate of Reaction (R) = k Cn 

Where n is the order of reaction, k is the rate constant, C is the concentration of a species either reactant or product which is selected for kinetic analysis and R is the rate of reaction with respect to that species divided by the respective stoichiometric number. The rate may be found by plotting the concentration of the species against time and then drawing tangents to this curve. The values of the tangents will be equal to the rate of reaction with respect to a selected species.

The linear form of the above equation is:

ln(R) = ln(k) + n ln(C)

Thus a plot of the ln(R) against ln(C) will be a straight line whose slope S is equal to:

S = n (order of reaction)

and Intercept I will be equal to:

I = ln(k)    =>    k = eI (rate constant)

The slope and intercept may be found by the application of least squares to the the kinetic data according to the linear form of the equation.

Instead concentration, you can measure the rate of heat evolution/consumption or the mass loss by using thermoanalytical techniques, such as DSC or TG. Then, the reaction kinetics can be treated by the isoconversional methods where the conversion function is not needed to be known. Please, see the file attached.

Kindest regards,

Peter Simon.

Thank you for your reply!

I think rate of a reaction id directly proportional to the reactant that is available(after being consumed or after being converted in to product)

But this concept is not going to fit with product concentration right?

Again in differential method  the tangents should be drawn.

how we are going to plot the tangents in excel?

If we are taking the linear form of the equation, perhaps we are considering the reaction as 1 st order.

So can we get the exact order and k?

Can anyone send me some papers ,about reaction rate determination for product formation,where product concentration only taken into consideration ,not the reactant concentration?

Dear Pattanaik, I have performed some example calculations for you. Hope this will be beneficial to you. 

For theoretical details there are many good books on the topic for example Elements of Chemical Reaction Engineering 4th Ed - H. Scott Fogler

Thank you very much danish for your reply !

I will surely go through this and ask you if i ll have some doubts

It is difficult to get rate from the product only unless we have the full information of the product branching ratios. For example, if a reaction have two parallel product channels as A --> B and A --> C, and assume both are 1st-order to A. Then the concentrations of B and C will increase, and we can fit the curve to [B](t) = B(t=infinite)*[1-exp(-(k1+k2)t)]. So what we have is the summation of k1 and k2, instead of individual k1 or k2.

A lot of other things can spoil it further. Product B may undergo futher reaction, or different product channels may have different orders.

  Dear Danish !

 If possible could you send me some paper related to determination  of kinetics by considering product formation,it will be more helpful as I am not getting any

Dear Mr. Wang, complexities are the part of every discipline in academics, but the beginners are not introduced to such complexities at the start. 

The question of Pattanaik was related to the very basic concepts in chemical kinetics and was accordingly tried to answered.

I agree with your argument and let me say that degree of complexities is much more higher than stated. Anyway thank you very much for your expert comment. 

In best of my knowledge, the initial concentration of reactant and time dependent concentration after reaction are required to determine rate constant and the rate of the reaction.

Dear Lopa,

what is your final goal? Why you need to know the reaction rate law? The chemical kinetics is one the most powerful tool to study the reaction mechanism. It's also used to build a mathematical model of the chemical process. Otherwise the study of the reaction kinetics is a waste of time. 

Dear Yurii!

I want to determine how fast my product is forming.

It will help me to optimize my reaction time

You don't need the detailed kinetic study to minimally optimize your system. Just vary the key experimental conditions, see the response of the system, and choose the best set of parameters. A full optimization would require years of hard work of a highly qualified team of scholars. 

Hi

Can you please find the attached image that shows the equation I used during the calculation of reaction rate of conversion of butene

Have a very good day and best of luck

Initial and final concentrations of solute as well as solid phase surface active site concentration are required. 

Both initial and final concentrations are required to get kinetics and rate of the reaction.

How can we determine reaction order under experimental condition? is it possible to draw the change of chemical against time and use the regression model? Should we determine the reaction order by regression model here? or is there other way?