Tiêu đề 17.CHEMICAL KINETICS.pdf ✅

UNIT 03 CHEMICAL KINETICS Exercise 1: NCERT Based Topic-wise MCQs 3.0 INTRDUCTION 1. Chemical Kinetics deals with NCERT Page-95 (a) reaction rate and mechanisms (b) Feasibility of the reaction (c) Energy content of the reaction (d) All of these 3.1 RATE OF A CHEMICAL REACTION 2. The rate law for the single- step reaction 2A + B ⟶ 2C, is given by: NCERT Page-100, 101 (a) rate = k[A].[B] (c) rate = k[2A] ⋅ [B] (b) rate = k[A] 2 ⋅ [B] (d) rate = k[A] 2 ⋅ [B] ∘ 3. Consider the reaction NCERT Page-99 N2(g) + 3H2(g) ⟶ 2NH3(g) The equality relationship between d[NH3 ] dt and − d[H2 ] dt is (a) + d[NH3 ] dt = − 2 3 d[H2 ] dt (b) + d[NH3 ] dt = − 3 2 d[H2 ] dt (c) d[NH3 ] dt = − d[H2 ] dt (d) d[NH3 ] dt = − 1 3 d[H2 ] dt 4. The rate of reaction (a) increases as the reaction proceeds (b) decreases as the reaction proceeds (c) remains the same as the reaction proceeds (d) may decrease or increase as the reaction proceeds 5. The unit of rate of reaction is NCERT Page-97 (a) mol/dm3 (b) mol/ pound (c) mol/dm3 sec (d) mol/cm3 6. In the rate equation, when the conc. of reactants is unity then rate is equal to NCERT Page-109 (a) specific rate constant (b) average rate constant (c) instantaneous rate constant (d) None of above
7. The rate of reaction between two specific time intervals is calle NCERT Page-97 (a) instantaneous rate (b) average rate (c) specific rate (d) ordinary rate 8. At the beginning, the decrease in the conc. of reactants is (a) slow (b) moderate (c) rapid (d) None of above 9. The average rate and instantaneous rate of a reaction are equal NCERT Page-97 & 98 (a) at the start (b) at the end (c) in the middle (d) when two rate have time interval Δt → 0 10. For a given chemical reaction γ1A + γ2B → γ3C + γ4D Concentration of C changes from 10mmoldm−3 to 20mmoldm−3 in 10 seconds. Rate of appearance of D is 1.5 times the rate of disappearance of B which is twice the rate of disappearance A. The rate of appearance of D has been experimentally determined to be 9m mol dm−3 s −1 . Therefore the rate of reaction is NCERT Page-98 & 99 (a) 1 (b)3 (c)2 (d)0 11. The rate of the reaction 2N2O5 → 4NO2 + O2 can be written in three ways : NCERT Page-99 −d[N2O5 ] dt = k[N2O5 ]; d[NO2 ] dt = k ′ [N2O5 ] d[O2 ] dt = k ′′[N2O5 ] The relationship between k and k ′ and between k and k ′′ are: (a) k ′ = 2k; k ′ = k (b) k ′ = 2k; k ′′ = k/2 (c) k ′ = 2k; k ′′ = 2k (d) k ′ = k; k ′′ = k 12. The reaction between X and Y is first order with respect to X and zero order with respect to Y. NCERT Page-101 & 102 Experiment [X] molL −1 [y] molL −1 Initial rate molL −1min −1 I. 0.1 0.1 2 × 10−3 II. L 0.2 4 × 10−3 III. 0.4 0.4 M × 10−3 IV. 0.1 0.2 2 × 10−3 Examine the data of table and calculate ratio of numerical values of M and L. (Nearest inetger) (a) 0.4,8,0.2 (b) 0.2,8,40 (c) 2,0.8,40 (d) 0.8,2,40
3.2 FACTORS INFLUENCING RATE OF A REACTION 13. Which one of the following statements for the order of a reaction is incorrect? NCERT Page-102 (a) Order can be determined only experimentally. (b) Order is not influenced by stoichiometric coefficient of the reactants. (c) Order of reaction is sum of power to the concentration terms of reactants to express the rate of reaction. (d) Order of reaction is always whole number. 14. The rate of the reaction 2NO + Cl2 ⟶ 2NOCl is given by the rate equation rate = k[NO2 [Cl2 ] The value of the rate constant can be increased by: (a) increasing the concentration of NO. (b) increasing the temperature. (c) increasing the concentration of the Cl2 (d) doing all of the above 15. Units of rate constant of first and zero order reactions in terms of molarity M unit are respectively (a) sec−1 , Msec−1 NCERT Page-103 (b) sec−1 , M (c) Msec−1 , sec−1 (d) M, sec−1 . 16. A reaction involving two different reactants can never be (a) bimolecular reaction (b) second order reaction (c) first order reaction (d) unimolecular reaction 17. 3A → B + C, it would be a zero order reaction when (a) the rate of reaction is proportional to square of concentration of A (b) the rate of reaction remains same at any concentration of A (c) the rate remains unchanged at any concentration of B and C (d) the rate of reaction doubles if concentration of B is increased to double 18. For the following homogeneous reaction, NCERT Page-103 A + B → k C the unit of rate constant is (a) sec−1 (b) sec−1molL −1 (c) sec−1 mol−1L (d) sec−1mol−2L 2 19. Velocity constant k of a reaction is affected by (a) change in the concentration of the reactant (b) change of temperature (c) change in the concentration of the product (d) None of the above 20. In the reaction 2A + B → A2B, if the concentration of A is doubled and that of B is halved, then the rate of the reaction will: (a) increase 2 times (b) increase 4 times (c) decrease 2 times (d) remain the same 21. The order of a reaction, with respect to one of the reacting component Y, is zero. It implies that: (a) the reaction is going on at a constant rate NCERT Page-102, & 105
(b) the rate of reaction does not vary with temperature (c) the reaction rate is independent of the concentration of Y (d) the rate of formation of the activated complex is zero 22. The unit of rate constant for a zero order reaction is NCERT Page-103 (a) molL −1 s −1 (c) L 2mol−2 s −1 (b) Lmol−1 s −1 (d) s −1 23. The order of a reaction with rate equal to k[A] 3/2 [B] −1/2 is: (a) 1 (b) − 1 2 (c) − 3 2 (d) 2 24. For the reaction, CH3COCH3 + I2 → H+ products. The rate is governed by expression dx dt = k[ acetone ][H +] The order w.r.t. I2 is: (a) 1 (b) 0 (c) 3 (d) 2 25. The rate constant for the reaction 2N2O5 ⟶ 4NO2 + O2 is 3.10 × 10−5 sec−1 . If the rate is 2.4 × 10−5mollitre−1 sec−1 then the concentration of N2O5 (in mol litre−1 ) is : (a) 0.04 (b) 0.8 (c) 0.07 (d) 1.4 26. The rate law for a reaction between the substances A and B is given by Rate = k[A] n [B] m On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as (a) (m + n) (b) (n − m) (c) 2 (n−m) (d) 1 2 (m+n) 27. Which one of the following reactions is a true first order reaction? NCERT PAGE-112 (a) Alkaline hydrolysis of ethyl acetate (b) Acid catalyst hydrolysis of ethyl acetate (c) Decomposition of N2O (d) Decomposition of gaseous ammonia on a hot platinum surface 28. What is order with respect to A, B, C, respectively NCERT PAGE- 101 [A] [B] [C] rate (M/ sec. ) 0.2 0.1 0.02 8.08 × 10−3 0.1 0.2 0.02 2.01 × 10−3 0.1 1.8 0.18 6.03 × 10−3 0.2 0.1 0.08 6.464 × 10−2 (a) −1,1,3/2 (b) −1,1,1/2 (c) 1,3/2, −1 (d) 1, −1,3/2