Certainly, I can provide some guidance on how to titrate citric acid using sodium hydroxide (NaOH). To determine the percentage of citric acid in your 10% citric acid solution, you can perform a simple acid-base titration.
Here's a step-by-step process:
Materials Needed:
10% citric acid solution
Sodium hydroxide (NaOH) solution
pH indicator (such as phenolphthalein)
Burette (for accurate dispensing)
Erlenmeyer flask or beaker
Distilled water (for dilution, if necessary)
Procedure:
Measure a specific volume of the 10% citric acid solution. For instance, you can take 10 mL of the solution in an Erlenmeyer flask or beaker.
Add a few drops of a pH indicator (phenolphthalein is a common choice). The solution should remain colorless or pale yellow at this point.
Titrate the citric acid solution with sodium hydroxide (NaOH) solution. Slowly add NaOH solution drop by drop while stirring the citric acid solution. Continue adding NaOH and stirring until the color changes from colorless (or pale yellow) to a light pink or some other color depending on the indicator used. The color change signifies that the citric acid has been neutralized by the NaOH.
Note the volume of NaOH solution required to achieve the color change. This volume represents the amount of NaOH needed to neutralize the citric acid in your measured sample.
Calculate the percentage of citric acid in the 10% citric acid solution using the volume of NaOH solution and the molarities of both citric acid and NaOH. Citric acid is a weak triprotic acid, so its molecular weight (MW) is 192.13 g/mol. The molecular weight of NaOH is 40.00 g/mol.
Using the equation:
% Citric Acid = [(Volume of NaOH solution) × (Molarity of NaOH) × (MW of citric acid) × 100] / (Volume of citric acid sample × 10)
The "10" in the denominator is because you started with a 10% citric acid solution.
Remember to perform the calculation carefully and ensure that you're using the correct molarities and measurements.
