" /> -->

#### Chemical Kinetics Model Question Paper

12th Standard EM

Reg.No. :
•
•
•
•
•
•

Chemistry

Time : 01:00:00 Hrs
Total Marks : 40
5 x 1 = 5
1. For a reaction Rate = kacetone[]32 then unit of rate constant and rate of reaction respectively is

(a)

(mol L-1 S-1),(mol1/2L1/2S-1)

(b)

(mol-1/2L1/2s-1),(mol L-1s-1)

(c)

(mol1/2L1/2s-1),(molL-1s-1)

(d)

(molLs-1),(mol1/2L1/2s)

2. The addition of a catalyst during a chemical reaction alters which of the following quantities? (NEET)

(a)

Enthalpy

(b)

Activation energy

(c)

Entropy

(d)

Internal energy

3. Which of the following does not affect the rate of reaction?

(a)

Amount of the reactant taken

(b)

Physical state of the reactant

(c)

∆H of reaction

(d)

Size of vessel

4. Which order reaction obeys the expression ${ t }_{ \frac { 1 }{ 2 } }\alpha \frac { 1 }{ \left[ A \right] } ?$

(a)

First

(b)

Second

(c)

Third

(d)

Zero

5. The addition of a catalyst during a chemical reaction alters which of the following quantities?

(a)

Activation energy

(b)

Entropy

(c)

Internal energy

(d)

Enthalpy

6. 5 x 2 = 10
7. Define half life of a reaction. Show that for a first order reaction half life is independent of initial concentration

8. Explain the rate determining step with an example.

9. H2(g) + Cl2(g) $\overset { hv }{ \longrightarrow }$ 2HCl(g). The reaction proceeds with a uniform rate throughout. What do you conclude?

10. Explain how will you find activation energy of a reaction by graphical method. (or) Draw the graph between log k vs $\frac { 1 }{ T }$. What is the relationship between its slope and activation energy.

11. The rate of the reaction X+2y⇾ product is 4x10-3 mol L-1S-1, if [X]=[Y]=0.2M and rate constant at 400K is 2x10-2s-1, What is the overall order of the reaction

12. 5 x 3 = 15
13. Explain briefly the collision theory of bimolecular reactions

14. A gas phase reaction has energy of activation 200 kJ mol-1. If the frequency factor of the reaction is is 1.6 X1013s-1 Calculate the rate constant at 600 K.(e-40.09=3.8X10-48)

15. Give examples for first order reaction.

16. The decomposition of NH3 on platinum surface is zero order reaction what are the rates of production of N2 and H2 if k = 2.5 X 10-4 mol+ L S-1.

17. The rate constant for a first order reaction is 60 S-1. How much time will it take to reduce the initial concentration of the reactant to its ${ \frac { 1 }{ 16 } }^{ th }$ value?

18. 2 x 5 = 10
19. The activation energy of a reaction is 225 k Cal mol-1 and the value of rate constant at 40°C is 11.8X10-6s-1Calculate the frequency factor, A.

20. For the reaction R - P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and second.