Explore BrainMass

# Butyric Acid and Hydrazoic Acid

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

Hydrazoic acid, HN3, and butyric acid, HC4H7O2, are both weak monoprotic acids. Their pKa values (at 25oC) are 4.72 and 4.82, respectively. What is [C4H7O2-] in a solution in which the stoichiometric concentrations of HN3 and HC4H7O2 are 0.165 mol/L and 1.19x10-6 mol/L, respectively?

Hints:

1. The stoichiometric concentration refers to the total concentration in solution (i.e. it is the total amount of acid dissolved in solution). For example, when you dissolve 0.1 mol of HA in water to make 1.0 L of solution, the stoichiometric concentration of HA is 0.1 mol/L. The equilibrium concentration of HA will be less than the stoichiometric concentration because some or all of HA ionizes.
2. In this problem, you are dealing with a mixture of two weak monoprotic acids, HA and HB. However, the stoichiometric concentration of HA is much greater than HB. Consider first the ionization of HA and then consider the implications that this has on the ionization of HB.

https://brainmass.com/chemistry/acid-and-base-organic-chemistry/butyric-acid-hydrazoic-acid-265175

#### Solution Preview

Please see the attached file for the complete solution.
Thanks for using BrainMass.

Mixture of 2 Monoprotic Weak Acids-calculating the pH
Nitrous acid, HNO2, and butyric acid, HC4H7O2, are both weak monoprotic acids. Their pKa values (at 25oC) are 3.14 and 4.82, respectively. What is [C4H7O2-] in a solution in which the stoichiometric concentrations of HNO2 and HC4H7O2 are 0.113 mol/L and 1.51x10-6 mol/L, respectively?

Hints:
1. The stoichiometric concentration refers to the total concentration in solution (i.e. it is the total amount of acid dissolved in solution). For ...

#### Solution Summary

This solution explains how to calculate the concentration of the butyrate ion (C4H7O2-) in a solution of hydrazoic acid and butyric acid.

\$2.19