Advertisements
Advertisements
Question
In a reaction between A and B, the initial rate of reaction (r0) was measured for different initial concentrations of A and B as given below:
| A/mol L−1 | 0.20 | 0.20 | 0.40 |
| B/mol L−1 | 0.30 | 0.10 | 0.05 |
| r0/mol L−1 s−1 | 5.07 × 10−5 | 5.07 × 10−5 | 1.43 × 10−4 |
What is the order of the reaction with respect to A and B?
Advertisements
Solution
Suppose the order of the reaction with respect to A is m and with respect to B is n.
∴ Rate (r0) = k[A]m [B]n
For the given data, we have,
Rate (r1) = 5.07 × 10−5
= k (0.20)m × (0.30)n ...(i)
Rate (r2) = 5.07 × 10−5
= k (0.20)m × (0.10)n ...(ii)
Rate (r3) = 1.43 × 10−4
= k (0.40)m × (0.05)n ...(iii)
Dividing eq. (i) by eq. (ii), we have,
`(5.07 xx 10^-5)/(5.07 xx 10^-5) = (k (0.20)^m xx (0.30)^n)/(k (0.20)^m xx (0.10)^n)`
⇒ 1 = (3)n
⇒ n = 0
Dividing eq. (iii) by eq. (ii) and putting the value of n, we get,
`(1.43 xx 10^-4)/(5.07 xx 10^-5) = (k (0.40)^m xx (0.05)^0)/(k (0.20)^m xx (0.10)^0)`
⇒ `(1.43 xx 10^-4)/(5.07 xx 10^-5)` = 2m
⇒ (2)m = 2.82
⇒ m log10 2 = log10 2.82 = 0.45
⇒ m = `0.45/(log_10 2)`
= `0.45/0.3010`
= 1.49
= 1.50
Hence, the order with respect to A is 1.5, and the order with respect to B is 0.
RELATED QUESTIONS
A reaction is second order in A and first order in B.
(i) Write the differential rate equation.
(ii) How is the rate affected on increasing the concentration of A three times?
(iii) How is the rate affected when the concentrations of both A and B are doubled?
For a reaction A + B ⟶ P, the rate is given by
Rate = k [A] [B]2
What is the overall order of reaction if A is present in large excess?
For the hydrolysis of methyl acetate in aqueous solution, the following results were obtained :
| t/s | 0 | 30 | 60 |
| [CH3COOCH3] / mol L–1 | 0.60 | 0.30 | 0.15 |
(i) Show that it follows pseudo first order reaction, as the concentration of water remains constant.
(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.
(Given log 2 = 0.3010, log 4 = 0.6021)
For a chemical reaction R → P, the variation in the concentration (R) vs. time (t) plot is given as:
(i) Predict the order of the reaction.
(ii) What is the slope of the curve?
(iii) Write the unit of rate constant for this reaction.
For the reaction:
\[\ce{2A + B -> A2B}\]
the rate = k[A][B]2 with k = 2.0 × 10−6 mol−2 L2 s−1. Calculate the initial rate of the reaction when [A] = 0.1 mol L−1, [B] = 0.2 mol L−1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L−1.
A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is doubled?
A reaction is first order in A and second order in B. How is the rate affected when the concentrations of both A and B are doubled?
Molecularity of a reaction _____________.
Which of the following statement is true for order of a reaction?
Which of the following statements is not correct about order of a reaction.
The value of rate constant of a pseudo first order reaction ______.
For a complex reaction:
(i) order of overall reaction is same as molecularity of the slowest step.
(ii) order of overall reaction is less than the molecularity of the slowest step.
(iii) order of overall reaction is greater than molecularity of the slowest step.
(iv) molecularity of the slowest step is never zero or non interger.
Why is the probability of reaction with molecularity higher than three very rare?
Why molecularity is applicable only for elementary reactions and order is applicable for elementary as well as complex reactions?
Why can we not determine the order of a reaction by taking into consideration the balanced chemical equation?
Assertion: Order of the reaction can be zero or fractional.
Reason: We cannot determine order from balanced chemical equation.
Assertion: Rate constants determined from Arrhenius equation are fairly accurate for simple as well as complex molecules.
Reason: Reactant molecules undergo chemical change irrespective of their orientation during collision.
Use Molecular Orbital theory to determine the bond order in each of species, [He2j+ and [He2]2+?
For a first order A → B, the reaction rate at reactant concentration of 0.01 m is found to be 2.0 × 10–5. The half-life period of reaction.
Which of the following statement is true?
