Determining Concentration of Sodium Hydroxide via Titration

Experiment Overview

• Objective: Determine the concentration of a sodium hydroxide (NaOH) solution by titrating it with solid oxalic acid.

Chemical Reaction

• Oxalic Acid Structure: Contains two acidic hydrogens.
• Reaction:
  • Oxalic acid (aqueous) + Sodium hydroxide (aqueous) → Sodium oxalate (aqueous) + Water.
  • Requires 2 moles of NaOH for each mole of oxalic acid.

Procedure

1. Preparation:
   • Oxalic Acid: Measured in grams and dissolved in water (25 ml).
   • Sodium Hydroxide: Placed in a burette.
2. Titration Process:
   • Mix NaOH with oxalic acid in an Erlenmeyer flask.
   • Use phenolphthalein as an indicator (solution turns pink when balanced).
3. Key Measurements:
   • Mass of oxalic acid.
   • Volume of NaOH dispensed from the burette.

Calculation of NaOH Concentration

• Moles of NaOH: Determined from moles of oxalic acid (mass-based calculation).
• Volume of NaOH: Read from burette, noting that volume readings increase downwards.
• Concentration Calculation: Moles of NaOH / Volume of NaOH in liters.

Trials

• Trial 1:
  • Oxalic Acid: 0.2911 grams.
  • Perform calculations using initial and final burette volumes.
• Trial 2:
  • Oxalic Acid: 0.3312 grams.
  • Repeat procedure and calculations.
• Trial 3:
  • Oxalic Acid: 0.2874 grams.
  • Consistent procedure and calculations.

Results and Analysis

• Average NaOH Concentration: Calculated from all three trials.
• Future Application: Use average concentration in subsequent labs to determine unknown acid concentrations.

Instructions for Assignment

• Record and utilize data from trials for calculations.
• Input results into a Canvas assignment for evaluation.