Imidazole (Im) can react with H+ or H2O to form positively charged imidazole (ImH+). The r...

Imidazole (Im) can react with H+ or H2O to form positively charged imidazole (ImH+). The reaction mechanisms are

a. What is the value of the equilibrium constant for the ionization of imidazole (ImH+ ⇋ Im + H+)?

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b. Write the differential equation for the net rate of formation of ImH+.

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c. If the pH is suddenly changed for a solution of 0.1 M imidazole in water from pH 7 to pH 4, what is the rate- determining step for the appearance of ImH+ at pH 4?

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d. What is the value of the initial rate of increase of ImH+ at pH 4?

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e. The rate coefficients k1 andk-1 both depend on temperature. Would you expect them to decrease or increase with increasing temperature? Which would you expect to change most with temperature and why?

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f. Predict the sign of the heat of ionization for imidazole based on your answer to part (e). The experimental heat of ionization is positive.