CBSE Guess > Papers > Important Questions > Class XII > 2007 > Chemistry > Chemical Kinetics
Chemical Kinetics
Q. 1. 2NO2+F2--> 2NO2F. Write the rate of reaction in terms of (a) rate of formation of NO2F (b) rate of disappearance of NO2 (c) rate of disappearance of F2.
Q. 2. The decomposition of NH3 follows zero order. 2 NH3→ N2+3H2 . Find the rate of production of N2 andH2.K = 2.5 x 10-4 MS-1. Also find rate of decomposition of NH3.
Q. 3. 2A+B+C→A2B + C Rate=K(A)(B)2 K=2x10-6M−2S-1. Calculate the initial rate when (A)=0.1M (B) = 0.2M (C)=0.6M. Find the rate when 0.04mole of (A) is consumed.
Q. 4. 2NO2+F2→2NO2F
Experiment ; |
(NO2)M |
(F2) M |
Rate(M/S) |
| 1 | 0.2 |
0.05 |
0.006 |
| 2 | 0.4 |
0.05 |
0.012 |
| 3 | 0.8 |
0.10 |
0.048 |
Find the order with respect to NO2 and F2. Also find the overall order of the reaction. Deduce the mechanism of the reaction.
Q. 5. A first order reaction is 20%complete in 10minutes. Find the time taken for 80%completion of the reaction. Also find the half life of the reaction.
Q. 6. Show that(a) 2t (1/2) = t (3/4) (b) Half life of a reaction is 10seconds.Find t (2/3),
Q. 7. The pressure of a gas decomposing at a metal surface of a solid catalyst are given below:
t/s |
0 |
100 |
200 |
300 |
P/Pa |
4.00x102 |
3.50x103 |
3.00x103 |
2.5x103 |
Determine the order of the reaction. Find the rate Constant and the half life of the reaction.
Q. 8. Hydrolysis of methyl acetate in aqueous solution has been studied by titrating liberated acetic acid with NaOH rate =K(CH3COOCH3) (H2O)
t/min |
0 |
30 |
60 |
90 |
c/M |
0.8500 |
0.8004 |
0.7538 |
0.7096 |
Show that it follows pseudo first order reaction as the concentration of water remains constant (1L of water=1000g Of water=1000/18=55.5M) What is the value of K?
Q. 9. The rates of a reaction starting with initial concentrations 2 x 10-3 M and1 x 10-3 M are 2.4 x 10-4 M/s and 0.6 x 10-4 M/s respectively. Find the order of the reaction and rate constant K.
Q. 10. A + 5B + 6C → 3L + 3M
Experiment |
(A)M |
(B)M |
(C)M |
Rate M/minute |
| 1. | 0.02 |
0.02 |
0.02 |
0.00208 |
| 2. | 0.01 |
0.02 |
0.02 |
0.00104 |
| 3. | 0.02 |
0.04 |
0.02 |
0.00416 |
| 4. | 0.02 |
0.02 |
0.04 |
0.00832 |
Determine the order with respect to each reactant. Find K .Calculate the initial rate when concentration of each reactant is 0.01M.Find the initial rate of change in concentrations of B and L
Q. 11. Rate of a reaction becomes 1.414 times when concentration of the reactant is doubled. Find the order of the reaction.
Q. 12. (a) show that for a first order reaction t½ is independent of the initial concentration of the reactant. (b) show that for a zero order reaction t½ is directly proportional to initial concentration of the reactant and inversely proportional to rate constant.
Q. 13. Rate constant of a reaction is 2M-1 S-1 at 700K and 32 M-1 S-1 at 800K.Find Ea
Q. 14. Rate of a reaction becomes 4 times when temperature changes from 270C to 370C. Find Ea.
Q. 15. Rate constant of a reaction at 700K and 760K are 0.01 M-1 S-1 and 0.105 M-1 S-1 respectively. Find A and Ea .
Q. 16. Rate constant of a reaction increases by 7% and the equilibrium constant increases by 3% when the temperature changes from 300K to 301k.Find Ea for the for ward and backward reaction.
Q. 17. Rate = K1(NH3)|1 + K2(NH3) Find the order when concentration of (a)NH3 is very low (b) when Pt surface is completely covered NH3 2NH3 → N2+3H2 using Pt as a catalyst.
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