Question

1.) Quantify the pH for a solution prepared by dissolving 0.050 moles of Acetic Acid (CH3COOH) and 0.20 moles of Sodium Acetate (CH3COONa) in water and adjusting the volume to 500 mL. The pka for Acetic Acid (CH3COOH) is 4.75.

2.) Should 0.010 moles of NaOH be added to this buffer solution, quantify the resultant pH for the solution.

Answer 1

1. Use the Henderson-Hasselbalch equation. Substitute into the HH equation and calculate pH.

2. Set up an ICE chart using
.......CH3COOH + OH^- --> CH3COONa + H2O

and substitute the E line of the ICE chart into the HH equation and sole for the new pH.

Answer 2

For #1, would I have to multiply 500 mL to 0.050 moles and 0.20 moles?

Or can I just set it up like this below and solve for it?

pH=4.75 + log [0.20]/[0.050]