Lab Demonstration | Acid - Base Titration.

Ali Hayek

2 Nov 201508:18

Summary

TLDRThis video tutorial demonstrates the titration process, explaining its importance in determining the concentration of an unknown solution. The presenter uses hydrochloric acid as the analyte and sodium hydroxide as the known titrant, detailing each step from preparation to observation of the color change with the phenolphthalein indicator. The video emphasizes careful measurement and repetition for accuracy. Finally, it outlines how to calculate the molarity of hydrochloric acid based on the titration results, providing viewers with both theoretical and practical insights into the procedure.

Takeaways

😀 Titration is used to determine the concentration of an unknown solution.
😀 A titrant is a solution of known concentration, often a strong base like sodium hydroxide (NaOH).
😀 The analyte is the solution being tested, such as hydrochloric acid (HCl) in this case.
😀 An accurate volume of the analyte is measured using a volumetric flask.
😀 An acid-base indicator, like phenolphthalein, is used to signal the endpoint of the titration.
😀 The color change of phenolphthalein from colorless to pink indicates the solution has become basic.
😀 During titration, the titrant should be added slowly as the endpoint approaches to avoid overshooting.
😀 Repeating the titration process helps ensure accuracy and reliability of results.
😀 The molarity of the analyte can be calculated using the formula involving the volume and concentration of the titrant.
😀 The stoichiometry of the reaction shows that one mole of H+ reacts with one mole of OH-.

Q & A

What is the purpose of performing a titration?
-Titration is used to determine the concentration of an unknown solution by reacting it with a titrant of known concentration.
What role does the titrant play in the titration process?
-The titrant is a solution with a known concentration that is added to the analyte to reach a chemical reaction endpoint.
What is the analyte in this titration experiment?
-The analyte is hydrochloric acid (HCl) in this experiment.
What indicator is used in this titration, and what are its color properties?
-Phenolphthalein is the indicator used, which is colorless in acidic solutions and turns pink in basic solutions.
How is the endpoint of the titration identified?
-The endpoint is identified when the pink color produced by phenolphthalein persists in the solution, indicating that all the acid has reacted with the base.
What volumes of solutions are used in this titration?
-10 mL of hydrochloric acid (HCl) is used as the analyte, and the volume of sodium hydroxide (NaOH) is recorded from the burette.
How many times should the titration be repeated for accuracy?
-It is recommended to repeat the titration two times to ensure accuracy and reliability in results.
What formula is used to calculate the molarity of HCl?
-The molarity of HCl can be calculated using the formula: Molarity of HCl = (Molarity of NaOH × Volume of NaOH) / Volume of HCl.
What stoichiometric relationship is important in this titration?
-The stoichiometric relationship is that one mole of H+ from HCl reacts with one mole of OH- from NaOH, indicating a 1:1 ratio.
What was the final calculated molarity of the hydrochloric acid solution?
-The final calculated molarity of the hydrochloric acid solution was 0.075 M.