Question

The order of a chemical reaction can be zero and even a fraction but molecularity cannot be zero or a non-integer. 

i) What do you mean by the order of a reaction? 

ii) What is the molecularity of a reaction? 

iii) The conversion of molecules ‘A’ to ‘B’ follows second order kinetics. If the concentration of A is increased to three times, how will it aect the rate of formation of ‘B’?

Answer 1

(i) It is sum of powers of the concentration – terms of the reactants in the rate law expression. 

(ii) The number of reacting species in an elementary reaction. 

(iii) Increases by 9 times. 

Rate = k[R]² 

Rate’= k[3R]² = 9 [R]² ; i.e., Rate = 9 Rate