Acid-Base Standardization Lab

Norah Albaiz

CHMY143-016

Katie Link

Lab Partner: Lydia Aman

Standardization of Acids and Bases

Purpose:

The purpose of this experiment was to determine the unknown concentrations of NaOH, HCl, H2SO4, Ba(OH)2 by using a technique called titration. Titration is where the titrant is added from a buret to a known quantity of an analyte until the reaction is complete. Acid-base titration techniques can help determine the unknown concentrations of the analytes. Titrations also allow us to find the pH, knowing the pH of a substance is often a key method to regulate the quality of foods and other products produced for sale.

Primary standard solutions are made by the exact direct amounts of the mass of solute and the volume of solution. Whereas, secondary standard solutions are solutions with concentration that cannot be determined directly from the amount of solute and volume of solution, but the concentration is found by specific analysis of the solution itself. It is typically standardized against a primary standard. The qualifications of a good primary standard are to be very pure, unchanging, to have a high molecular weight, and not be sensitive to the environment.

Procedure:

The KHP was dissolved in about 25 mL of water, 2 drops of phenolphthalein were added to the solution. A buret was rinsed three times with about 5 mL of NaOH, the buret was securely clamped to a ring stand. The buret was filled with NaOH solution to slightly above the zero mark. A waste beaker was placed under the apparatus and the stopcock was opened to run a small amount of solution out of the buret to remove any air bubbles from the stopcock. The initial volume on the buret was recorded. The stopcock was opened while the KHP solution was gently stirred. The solution turned faint pink, the stopcock was closed, and the final volume was recorded. The titration was