Compounds ‘A’ and ‘B’ react according to the following chemical equation.
The concentration of either ‘A’ or ‘B’ was changed keeping the concentrations of one of the reactants constant and rates were measured as a function of initial concentration. Following results were obtained. Choose the correct option for the rate equations for this reaction.
Experiment | Initial Concetration of [A]/molL-1 | Initial Concentration of [B]/molL-1 | Initial rate concentration of [C]/molL-1 S-1 |
1 | 0.30 | 0.30 | 0.10 |
2 | 0.30 | 0.60 | 0.40 |
3 | 0.60 | 0.30 | 0.20 |
(i) Rate =
(ii) Rate =
(iii) Rate =
(iv) Rate =
The answer is the option (ii)
We know that Rate of a reaction is
On doubling the concentration of B, keeping the concentration of A constant, the rate of formation of C increases by a factor of four. Thus, the rate of reaction is directly proportional to the square of concentration of B. However, on doubling the concentration of A, the rate of formation of C becomes the double of the initial value. Thus the rate is directly proportional to the first power of concentration of A. Hence Rate =