Question

Be sure to answer all parts. Sulfonation of benzene has the following mechanism: (1) 2 H2SO4 ⇌ H3O+ + HSO4− + SO3 [fast] (2) SO3 + C6H6 → H(C6H5+)SO3− [slow] (3) H(C6H5+)SO3− + HSO4− → C6H5SO3− + H2SO4 [fast] (4) C6H5SO3− + H3O+ → C6H5SO3H + H2O [fast] (a) Write the overall equation for this reaction. (b) Write the overall rate law for the initial rate of the reaction. Rate =

Answer 1

C6H6 + H2SO4 ---> C6H5SO3H + H2O

k [H2SO4]^2 [C6H6]

Step-by-step explanation:

In writing the rate equation for a reaction, all the steps in the reaction sequence are summed and transient intermediates are taken into consideration.

Writing rate equation began at the slowest step as shown in the image attached to this answer below. This is because the slowest step determines the rate of reaction. Concentration of intermediates are usually expressed in terms of concentration of reactants as intermediates do not enter the rate equation.