Answer Happy

The reaction between iodine ions and a Cobalt-complex
(Co(CN)5OH2− 2 )
Co(CN)5OH22− +
I− → Co(CN)5I3− +
H2O
is believe to follow the following reaction mechanism:
(1) Co(CN)5OH22- ⇐ k1 ==⇒ k−1
CO(CN)2− 5 + H2O
(2) Co(CN)2− 5 + I− k2 ==⇒
Co(CN)5I3−
where step (1) is associated with rate constants k1, k−1 and
step (2) is associated with rate constant k2.
(i) Write an equation for the rate of formation of Co(CN)5I
3−
(ii) Write the rate law for the intermediate complex, Co(CN)2− 5
.
(iii) Apply the steady state approximation and derive the rate
law for the formation of the Co(CN)5I 3− complex in terms of the
reactants.
(iv) Derive an expression for the rate law when the
concentration of iodine is very large. What step is then the rate
limiting step?
(v) Derive an expression for the rate law when the concentration
of iodine is very small. What step is then the rate limiting
step?
Co(CN),OH- + Iº + Co(CN)513- + H2O
ki k_1 (1) Co(CN)5OH;- *1 CO(CN)}- + H2O (2) Co(CN).- +1- + I- k2, Co(CN);13-