UNIT4

CHEMICAL KINETICS                 

    M.M. 20

 

1. A reaction is II order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is (i) doubled (ii) reduced to half.                                                                                          1

 

2. Calculate the half life of a first order reaction if the rate constant is 2 min. 1

 

 

3. For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.                                                                                                                       2

 

4. The following data were obtained during the first order thermal decomposition of SO₂Cl₂ at a constant volume SO₂Cl₂(g)            SO₂ (g)   +   Cl₂(g)                                                                                                     3

Experiment	Time (S-1)	Total pressure(atm)
1	0	0.5
2	100	0.6

Calculate the rat e of reaction when total pressure is 0.65 atm.

 

5. The rate constant of a reaction at 500 K and 700 K are 0.02 S^-1 and 0.07 S^-1 Calculate the value of Arrhenius parameters. 3

 

6. Explain the concept of activation energy and activated complex with the help of a diagram and example. 3

 

 

7. The activation energy for the reaction 2HI (g)           H₂ (g) + I₂ (g) is 209.5 KJ/mol at 581 K. Calculate the fraction is molecules of reactants having energy equal to or greater than activation energy.                2

 

8. Differentiate between rate of reaction and specific reaction rate. 2

 

 

9. What is meant by Pseudo first order reaction? In a pseudo order of ester hydrolysis of ester in water, following results are obtained: 3

Time(in s)	0	30	60	90
[ester] mol/L	0.55	0.31	0.17	0.085

• Calculate the average rate of reaction between the time intervals 30 to 60 seconds.
• Calculate the first order pseudo rate constant.