Laboratory Investigations Outline

KHP = KHC₈H₄O₄ = [K⁺][HC₈H₄O₄^-] salt.

HC₈H₄O₄^- is a monoprotic acid.

I. Standardization of NaOH(aq) Solution

• Prepare 125 mL of 0.5 M NaOH (from 5 M NaOH) in a tightly stoppered 250 mL erlenmyer flask

• Determine initial mass of KHP (± 0.001 g). Use about 0.5 – 0.8 g of KHP.

• Quantitatively transfer KHP to 125 mL erlenmeyer flask, add 30-40 mL DI water

• Rinse then fill buret with NaOH solution

• Record initial buret reading (± 0.01 mL)

• Titrate to pink phenolphthalein endpoint, record final NaOH buret reading

• Dispose of reaction solution down the drain

• Repeat with a second and third sample of KHP

II. Weight Percent of Commercial Vinegar Solution

• Determine initial mass of vinegar solution (± 0.001 g). Use 7-8 mL of vinegar.

• Quantitatively transfer vinegar to 125 mL erlenmeyer flask, add 20-30 mL DI water

• Fill buret with NaOH solution

• Record initial buret reading

• Titrate to pink phenolphthalein endpoint, record final NaOH buret reading

• Dispose of reaction solution down the drain

• Repeat with a second and third sample of vinegar.