Chemical Kinetics - Result Question 33

####33. The reaction of hydrogen and iodine monochloride is given as:

[2007]

H2(g)+2ICl(g)2HCl(g)+I2(g)

The reaction is of first order with respect to H2(g) and ICI(g), following mechanisms were proposed.

Mechanism A :

H2(g)+2ICl(g)2HCl(g)+I2(g)

Mechanism B:

H2(g)+ICl(g)HI(g); slow

HI(g)+ICl(g)HCl(g)+I2(g); fast

Which of the above mechanism(s) can be consistent with the given information about the reaction?

(a) A and B both

(b) neither A nor B

(c) A only

(d) B only

Show Answer

Solution:

  1. (d) As the slowest step is the rate determining step thus the mechanism B will be more consistent with the given information. Also because it involve one molecule of H2 and one molecule of ICl, it can be expressed as :

r=k[H2][ICl]

Which shows that the reaction is of first order w.r.t. both H2 & ICl.



NCERT Chapter Video Solution

Dual Pane