Diverse Examples of Titration Calculations

Explore practical examples of titration calculations for better understanding.
By Jamie

Introduction to Titration Calculations

Titration is a quantitative analytical method used to determine the concentration of a solute in a solution. This technique involves the gradual addition of a titrant (a solution of known concentration) to a sample solution until the reaction reaches its endpoint, which is often indicated by a color change or a pH change. Understanding titration calculations is essential for chemists and students alike, as it allows for accurate measurement and analysis in various applications, such as acid-base reactions, redox reactions, and more.

In this article, we will cover three diverse examples of titration calculations, illustrating different contexts and methodologies.

Example 1: Determining the Concentration of a Hydrochloric Acid Solution

In a laboratory setting, a student is tasked with determining the concentration of hydrochloric acid (HCl) in a solution using sodium hydroxide (NaOH) as a titrant. The student prepares a NaOH solution of known concentration, 0.1 M, and uses phenolphthalein as an indicator.

Calculation Steps:

  1. Volume of HCl solution used: 25.0 mL
  2. Volume of NaOH solution used at endpoint: 30.0 mL
  3. Concentration of NaOH: 0.1 M

Using the formula:

titration formula: C1V1 = C2V2

Where:

  • C1 = concentration of HCl
  • V1 = volume of HCl
  • C2 = concentration of NaOH
  • V2 = volume of NaOH

Plugging in the values:

  • C1 * 25.0 mL = 0.1 M * 30.0 mL
  • C1 * 25.0 mL = 3.0 mmol (since 0.1 M * 30.0 mL = 3.0 mmol)
  • C1 = 3.0 mmol / 25.0 mL = 0.12 M

Conclusion:

The concentration of the hydrochloric acid solution is found to be 0.12 M.

Example 2: Analyzing the Acidity of Vinegar

A food scientist is examining the acetic acid content in vinegar. Using a titration method with sodium hydroxide as the titrant, the scientist aims to measure the acidity accurately.

Calculation Steps:

  1. Volume of vinegar analyzed: 10.0 mL
  2. Volume of NaOH solution used at endpoint: 20.0 mL
  3. Concentration of NaOH: 0.1 M

Using the same titration formula:

C1V1 = C2V2

Where C1 is the concentration of acetic acid, and V1 is the volume of the vinegar solution. The values are:

  • C1 * 10.0 mL = 0.1 M * 20.0 mL
  • C1 * 10.0 mL = 2.0 mmol
  • C1 = 2.0 mmol / 10.0 mL = 0.20 M

Conclusion:

The concentration of acetic acid in the vinegar sample is calculated to be 0.20 M.

Note:

This analysis can help determine the quality of vinegar and ensure it meets dietary regulations.

Example 3: Redox Titration of Iron(II) with Potassium Permanganate

In a redox titration, a chemist is evaluating the iron content in a sample using potassium permanganate (KMnO4) as the titrant. The endpoint is indicated by a persistent pink color, signifying that all iron(II) ions have been oxidized.

Calculation Steps:

  1. Volume of iron(II) solution used: 50.0 mL
  2. Volume of KMnO4 solution used at endpoint: 15.0 mL
  3. Concentration of KMnO4: 0.02 M

For the reaction:

equation: 5 Fe^2+ + MnO4^- + 8 H^+ → 5 Fe^3+ + Mn^2+ + 4 H2O

From the stoichiometry, 1 mole of MnO4^- reacts with 5 moles of Fe^2+.

Using the titration formula:

  • 0.02 M * 15.0 mL = (C1 * 50.0 mL) / 5
  • 0.03 mmol = (C1 * 50.0 mL) / 5
  • C1 = (0.03 mmol * 5) / 50.0 mL = 0.003 M

Conclusion:

The concentration of iron(II) ions in the sample is calculated to be 0.003 M.

Note:

Redox titrations are crucial in various industries, including pharmaceuticals and food processing, for quality control and assurance.