PHYSICAL CHEMISTRY IN BRIEF

CHAP. 9: CHEMICAL KINETICS [CONTENTS] 303

9.4.9.4 Special cases

a) Both rate constants are the same,k 1 =k 2 =k. Then

cA=cA0e−kτ, cB=kcA0τe−kτ. (9.135)

b) The first reaction is much faster than the second,k 1 k 2. Then

cA≈ 0 , cB≈cA0e−k^2 τ, cC≈cA0−cB. (9.136)

c)The second reaction is much faster than the first,k 1 k 2. Then

cA=cA0e−k^1 τ, cB=cA0

k 1

k 2

≈ 0 , cC≈cA0−cA. (9.137)