dorebase2006
Dec21-10, 04:57 AM
1. The problem statement, all variables and given/known data
Consider the following mechanism:
(1) ClO^{-} (aq) + H2O (l) \Leftrightarrow HClO (aq) + OH^{-} (aq) [fast]
(2) I^{-} (aq) + HClO (aq) \rightarrow HIO (aq) + Cl^{-} (aq) [slow]
(3) OH^{-} (aq) + HIO (aq) \rightarrow H2O (l) + IO^{-} (aq) [fast]
Is the mechanism consistent with the actual rate law: rate = k[ClO^{-}][I^{-}]
2. The attempt at a solution
I can't eliminate the intermediate OH^{-} in my rate law. As far as I know, since the second step is slow, my rate should come from there, so rate = k_{2} [I^{-}][HClO]. Then I use the equilibrium (1) to express [HClO] in terms of [reactant]'s, but apparently [OH^{-}] is there, and I don't know how to continue with this.
Another problem with which I also have the same trouble is the following proposed mechanism for the sulfonation of benzene:
(1) H2SO4 \rightarrow H3O^{+} + HSO4^{-} + SO3 [fast]
(2) SO3 + C6H6 \rightarrow H(C6H5^{+})SO3^{-} [slow]
(3) H(C6H5^{+})SO3^{-} + HSO4^{-} \rightarrow C6H5SO3^{-} + H2SO4 [fast]
(4) C6H5SO3^{-} + H3O^{+} \rightarrow C6H5SO3H + H2O [fast]
Thanks in advance!
Consider the following mechanism:
(1) ClO^{-} (aq) + H2O (l) \Leftrightarrow HClO (aq) + OH^{-} (aq) [fast]
(2) I^{-} (aq) + HClO (aq) \rightarrow HIO (aq) + Cl^{-} (aq) [slow]
(3) OH^{-} (aq) + HIO (aq) \rightarrow H2O (l) + IO^{-} (aq) [fast]
Is the mechanism consistent with the actual rate law: rate = k[ClO^{-}][I^{-}]
2. The attempt at a solution
I can't eliminate the intermediate OH^{-} in my rate law. As far as I know, since the second step is slow, my rate should come from there, so rate = k_{2} [I^{-}][HClO]. Then I use the equilibrium (1) to express [HClO] in terms of [reactant]'s, but apparently [OH^{-}] is there, and I don't know how to continue with this.
Another problem with which I also have the same trouble is the following proposed mechanism for the sulfonation of benzene:
(1) H2SO4 \rightarrow H3O^{+} + HSO4^{-} + SO3 [fast]
(2) SO3 + C6H6 \rightarrow H(C6H5^{+})SO3^{-} [slow]
(3) H(C6H5^{+})SO3^{-} + HSO4^{-} \rightarrow C6H5SO3^{-} + H2SO4 [fast]
(4) C6H5SO3^{-} + H3O^{+} \rightarrow C6H5SO3H + H2O [fast]
Thanks in advance!