CHM 2046C Module 11 – Chapter 17 Sample Exam

Part E: Equilibria of Acids and Bases Calculations 10 points

Write the appropriate equilibrium constant expression for the following reaction::

A solution prepared from 0.055 mol of butanoic acid dissolved in sufficient water to give 1.0 L of solution has a pH of 2.72. Determine K_a for butanoic acid. The acid ionizes at according to the balanced equation.

CH₃CH₂CH₂CO₂H_(aq) + H₂O ó H₃O⁺¹ + CH₃CH₂ CH₂CO₂^-1_(aq)

	[CH3CH2 CH2CO2H]	[H3O^+1]	[CH3CH2 CH2CO2^-1]
Initial
Change
Equilibrium

What are the equilibrium concentrations of acetic acid, the acetate ion, and hydronium ion for a 0.10 M solution of acetic acid (K_a = 1.8 x 10^-5)? What is the pH of the solution?

Ionization Reaction(you write):

	[CH3CO2H]	[H3O^+1]	[CH3CO2^-1]
Initial
Change
Equilibrium

Part F: Hydrolysis Calculations 10 points

What is the pH of the bleach solution which is 5.25% by weight Sodium hypochlorite, NaClO?

The K_a of Hypochlorous acid is 3.5 x 10^-8