Consider the titration of a 20.0-mL sample of 0.105 M HC₂H₃O₂ with 0.125 M NaOH. Determine each quantity. b. the volume of added base required to reach the equivalence point

Verified step by step guidance

1. Determine the moles of acetic acid (HC2H3O2) present in the solution using the formula: \( \text{moles} = \text{concentration} \times \text{volume} \).
2. Use the balanced chemical equation for the reaction: \( \text{HC}_2\text{H}_3\text{O}_2 + \text{NaOH} \rightarrow \text{NaC}_2\text{H}_3\text{O}_2 + \text{H}_2\text{O} \). Note that the mole ratio between HC2H3O2 and NaOH is 1:1.
3. Since the mole ratio is 1:1, the moles of NaOH required to reach the equivalence point will be equal to the moles of HC2H3O2 calculated in the first step.
4. Calculate the volume of NaOH solution needed using the formula: \( \text{volume} = \frac{\text{moles}}{\text{concentration}} \).
5. Substitute the moles of NaOH and its concentration into the formula to find the volume of NaOH required to reach the equivalence point.

Key Concepts

Titration

Titration is a quantitative analytical technique used to determine the concentration of a solute in a solution. It involves the gradual addition of a titrant (a solution of known concentration) to a sample until a reaction reaches its equivalence point, where the amount of titrant equals the amount of substance in the sample. This process is often monitored using indicators or pH meters to identify the endpoint.

Equivalence Point

The equivalence point in a titration is the stage at which the amount of titrant added is stoichiometrically equivalent to the amount of substance present in the sample. At this point, the reaction between the acid and base is complete, and the pH of the solution changes significantly. Understanding the equivalence point is crucial for calculating the volume of titrant needed to neutralize the analyte.

Molarity and Volume Relationship

Molarity (M) is defined as the number of moles of solute per liter of solution. In titration calculations, the relationship between the molarity and volume of the acid and base is used to determine the volume of titrant required to reach the equivalence point. The formula M1V1 = M2V2 relates the molarity and volume of the acid (M1, V1) to the molarity and volume of the base (M2, V2), allowing for the calculation of the unknown volume.