Question

5. (16 marks) Data for the reaction A(g) +2B(g)2C(g) are given below at certain temperature, T: Initial [Alo (M) Initial (Blo (M) Experiment Initial Rate of C formed(M s 5.7x 10 4.55 x 10 0.02 0.02 1 2 0.04 0.04 3 0.02 0.04 2.28 x 10 (a) Find the rate law and the rate constant for this reaction (5 marks) (b) Calculate the initial rate of disappearance of reactant A for experiment 2 (4 marks) (c) If the proposed mechanism for the above reaction involved two steps as shown below Step 1: 2BI (where I is an intermediate) Step 2: A+I 2C. (i) Explain whether Step 1 or Step 2 is the rate determining step. (3 marks) 6

Answer 1

Comment in case of any doubt.

deci z = 14.5570) m nmn 2 .2 - 2 Bas Let sate, r=K[A] "EB)" - de 3; 45.74X1024K [O-02"[0.02) - *.55 XVÕ! = K[0-04)" (0.04)" ül 73=3x2.28x16' = 110.02)"? (0.04)" -) cilio divided by iis gives: en assenta =)2=2 >> m= l -(iv) ciis divided by co gives = 2.2 = 2m+ 8 5.7x102- >> 22=29*> mun= 3 = 1+0=3 (using (iv) ) naz using 6), m=1, n=2, me get * *5.7x0X= K (0.02 M)*(0.02 M)?=)}K= 3.56x1) 3-1 a mell rate constant sate law, frate= (3.560,00 m2 st) [A] [B] ²) 1 - do y = 543 dCC] aftur 55XÖ= (0.22.75MS-1 (6) It is not possible to decide which step is rate determining based on given data Slower of the two steps will be rate determining 2 Je