Chemistry/H2SO4-NaOH Titration

TITRATION OF SULPHURIC ACID WITH SODIUM HYDROXIDE Modified: November 3, 2002

INTRODUCTION
A TITRATION is a process in which a measured amount of a solution is reacted with a known volume of another solution (one of the solutions has an unknown concentration) until a desired end point is reached. (The “end point” of a titration is the point in the titration at which an indicator dye just changes colour to signal the stopping point of the titration.) In this experiment, you will use a PIPETTE to measure some sulphuric acid into a beaker. The sulphuric acid has an unknown concentration. Then you will fill a BURETTE with sodium hydroxide (a base) that has a known concentration. Because all the reactants and products in this reaction are colourless, an INDICATOR DYE is added to the sulphuric acid to let us know when all the acid present has been EXACTLY NEUTRALIZED by adding base. Finally, the sodium hydroxide in the burette is added to the acid/indicator solution until the indicator changes colour. (An indicator dye is a chemical that has a different colour in an acid and a base.)

CALCULATIONS

 * 1) Average the values for the total volumes of NaOH added.  If a third titration was required, average the two closest values.
 * 2) Use the values for the averaged total volume of NaOH added AND the NaOH concentration to calculate the moles of NaOH used.
 * 3) Write and balance an equation to show how H2SO4 reacts with NaOH in a neutralization equation.
 * 4) Calculate the moles of H2SO4 used in the reaction, using the moles of NaOH calculated in #2 and the balanced equation in #3.
 * 5) Calculate the molarity of the H2SO4, using the moles of H2SO4 calculated in #4 and the volume of H2SO4 recorded in your Data section.

DATA AND OBSERVATIONS
Identification letter of unknown H2SO4 = ____________________

1st Titration
NaOH concentration = _______________

Volume of pipette used for H2SO4 = ______________

Initial burette volume = (initial volume of NaOH) = ______________

Final burette volume = (final volume of NaOH = ______________

Total volume of NaOH added (difference between initial and final volumes) = ______________

2nd Titration
Initial burette volume = (initial volume of NaOH) = ______________

Final burette volume = (final volume of NaOH = ______________

Total volume of NaOH added (difference between initial and final volumes) = ______________

3rd Titration (if needed)
Initial burette volume = (initial volume of NaOH) = ______________

Final burette volume (= final volume of NaOH) = ______________

Total volume of NaOH added (difference between initial and final volumes) = ______________