Chapter 11, Problem 84QRT

Many biochemical reactions are catalyzed by acids. A typical mechanism consistent with the experimental results (in which HA is the acid and X is the reactant) is

Step 1: $\text{reversible HA}(\text{aq})\rightleftharpoons {\text{H}}^{+}(\text{aq})+{\text{A}}^{-}(\text{aq})\text{fast}$

Step 2: $\text{reversible X}(\text{aq})+{\text{H}}^{+}(\text{aq})\rightleftharpoons {\text{XH}}^{+}(\text{aq})\text{fast}$

Step 3: ${\text{XH}}^{+}(\text{aq})\to \text{products}\text{slow}$

1. (a) Derive the rate law from this mechanism.
2. (b) Determine the order of reaction with respect to HA.
3. (c) Determine how doubling the concentration of HA would affect the rate of the reaction.