Titration Experiment & Calculate the Molarity of Acetic Acid in Vinegar

Summary

This instructional video demonstrates the process of performing a titration between sodium hydroxide (NaOH) and acetic acid (vinegar), highlighting the importance of safety, accurate measurements, and careful technique. Viewers are guided through each step: from setting up the burette and adding the indicator, to carefully adding NaOH drop-by-drop until the endpoint is reached. The video also explains how to calculate the molarity of acetic acid using the titration data, including volume conversions, mole ratios, and the final calculation of the molarity. Key terms like equivalence point and endpoint are clearly defined for a better understanding of the titration process.

Takeaways

• 😀 Safety is crucial in titration experiments: wear goggles, gloves, and secure hair. Remove jewelry before starting.
• 😀 The burette is filled with a standardized titrant solution (NaOH), and the Erlenmeyer flask contains the analyte (acetic acid in vinegar).
• 😀 Phenolphthalein is a suitable indicator for titrations involving a strong base (NaOH) and a weak acid (acetic acid).
• 😀 Ensure to measure the volume of acetic acid accurately using a graduated cylinder or pipette before starting the titration.
• 😀 Add NaOH slowly from the burette to the acetic acid while swirling the flask to observe the color change indicating the endpoint.
• 😀 The endpoint is reached when the solution in the flask remains pink for 10 seconds or more.
• 😀 The equivalence point is the point at which the moles of titrant equal the moles of analyte, whereas the endpoint is indicated by the color change of the indicator.
• 😀 Always rinse down the sides of the Erlenmeyer flask with distilled water during the titration to avoid any errors from residual reactants.
• 😀 When approaching the endpoint, add NaOH drop by drop for higher accuracy and to avoid overshooting the equivalence point.
• 😀 After the titration, record the final burette volume with two decimal places and milliliters as the unit.
• 😀 To calculate the molarity of acetic acid, use the volume of NaOH, its molarity, and the stoichiometric relationship between NaOH and acetic acid from the balanced equation.

Q & A

What is the main goal of the titration in this video?

The main goal is to determine the molarity of acetic acid in vinegar by performing a titration with a standardized sodium hydroxide (NaOH) solution.

Why is safety important when performing a titration?

Safety is crucial because titrants and analytes such as sodium hydroxide and acetic acid are chemicals that can cause harm. Wearing goggles, gloves, and ensuring no jewelry or loose clothing prevents accidents.

What should you do if you get an acid or base on your skin during the titration?

You should immediately wash the affected area with copious amounts of water to neutralize the acid or base and prevent injury.

Why is it important to remove the funnel after filling the burette?

The funnel should be removed to avoid any contamination or inconsistent readings, as the burette needs to be filled only with the titrant solution during the titration process.

What is the purpose of using phenolphthalein in this titration?

Phenolphthalein is used as an indicator because it changes color at the endpoint of the titration. In this case, it shifts from colorless to pink when the titration reaches the equivalence point.

How do you know when the endpoint of the titration has been reached?

The endpoint is reached when a pink color persists for at least 10 seconds after the titrant is added, indicating that the moles of titrant and analyte have reacted in stoichiometric proportions.

What is the difference between the equivalence point and the endpoint?

The equivalence point is the actual point where the moles of titrant equal the moles of analyte, while the endpoint is indicated by a color change in the indicator, signaling that the equivalence point has been reached.

Why is it necessary to add distilled water during the titration?

Distilled water is used to rinse down any drops of titrant that may have clung to the sides of the Erlenmeyer flask, ensuring all of the titrant is involved in the reaction.

What calculation steps are involved in determining the molarity of acetic acid from the titration?

First, calculate the volume of sodium hydroxide used, then convert it to liters. Next, calculate the moles of NaOH using its molarity. Using the mole ratio from the balanced equation, find the moles of acetic acid, and finally calculate the molarity by dividing the moles of acetic acid by the volume of vinegar used.

How do you calculate the percent error in a titration experiment?

The percent error is calculated by subtracting the experimental molarity from the accepted molarity, dividing the difference by the accepted molarity, and multiplying by 100 to get the percentage error.