Acid Base Equilibrium

What is the common ion effect?

• The decrease in the solubility of a salt when the solution already contains one of the ions in the salt

• The increase in the concentration of hydrogen ions when a salt is added to a solution

• The assumption that the concentration of a common ion is initially zero

• The change in pH when a strong acid is added to a solution

According to Le Châtelier's principle, what happens when more of a common ion is added to a solution?

• The equilibrium is unaffected

• The equilibrium is pushed to the right, causing more hydrogen ions to be present

• The equilibrium is pushed to the left, causing fewer hydrogen ions to be present

• The pH of the solution decreases

What is the effect of increasing the concentration of the salt solution on the equilibrium position in a solution containing a weak acid and its conjugate base?

• The equilibrium will be pushed to the right

• The equilibrium will be pushed to the left

• The equilibrium will remain unchanged

• The equilibrium will fluctuate unpredictably

What is the pH of a solution containing 1.0 M HF and 1.0 M NaF, given that the K_a for HF is 7.2x10^-4?

• 3.14

• 4.00

• 7.00

• 11.00

What does a buffered solution resist?

• A change in temperature

• A change in pH when H+ or OH- are added

• A change in volume

• A change in concentration

Which of the following is an example of a weak acid and its salt that can be part of a buffered solution?

• HCl and NaCl

• HF and NaF

• H2SO4 and Na2SO4

• HNO3 and NaNO3

What is the Henderson-Hasselbalch equation used for?

• Calculating the molarity of a solution

• Calculating the pH of a buffer

• Determining the pOH of a solution

• Measuring the concentration of H+ ions

According to the Henderson-Hasselbalch equation, what is the pH of a buffer if the pKa is 4.74 and the ratio of the concentration of the salt (A-) to the acid (HA) is 1?

• 3.74

• 4.74

• 5.74

• 6.74

What should be done first when acid or base is added to a buffered solution?

• Perform an equilibrium calculation

• Do a stoichiometry calculation

• Measure the pH of the solution

• Dilute the solution

What is the change in pH when 0.010 mol NaOH is added to 1.0L of a buffered solution containing 0.50 M acetic acid and 0.50 M sodium acetate?

• pH increases by 5 pH units

• pH decreases by 5 pH units

• pH increases by 0.02 pH units

• pH decreases by 0.02 pH units