Abstract:
A rotating disc electrode method for iodine determination has been developed for the kinetic investigations of bromate-iodide reaction.
The fourth order rate law of the uncatalyzed reaction is confirmed in a nitrate medium with ionic strength 1.00 at 25° C. Ko is found to be 50.26 M-3sec-1.
Molybdate (VI) catalysis of bromate-iodide reaction has been shown, under the similar conditions, to obey the rate expression:
Ko is 1.201 x 10 5 M-3 sec-1
The nature of molybdate (VI) species in solutions has been investigated. It has been concluded that at the pH values (2-3) and Mo(VI) concentration range (of order 10-6M) studied, molybdate (VI) exists predominantly as H2MoO4, HMoO4- and MoO42- species. A mechanism for the Mo(VI) catalyzed reaction has been postulated in the light of available information.
