Understanding the Titration Reaction

Oct 13, 2025 by wbrum.org 149 views

A Comprehensive Guide to Titration: Calculating the Volume of Base Required to Reach Equivalence Point

Titration is a fundamental technique in chemistry used to determine the concentration of a substance in a solution. It involves the reaction of a known concentration of one substance (the titrant) with a solution of unknown concentration (the analyte) until the reaction is complete, known as the equivalence point. In this article, we will explore the concept of titration and calculate the volume of base required to reach the equivalence point in a specific titration reaction.

Understanding the Titration Reaction

The titration reaction we will be discussing involves the reaction of phosphoric acid (H3PO4) with sodium hydroxide (NaOH). The balanced chemical equation for this reaction is:

H3PO4 + 3NaOH → Na3PO4 + 3H2O

In this reaction, one mole of phosphoric acid reacts with three moles of sodium hydroxide to form one mole of sodium phosphate and three moles of water.

Calculating the Number of Moles of Phosphoric Acid

To calculate the number of moles of phosphoric acid, we need to know the volume and concentration of the solution. The given information is:

Volume of phosphoric acid solution: 13.8 mL
Concentration of phosphoric acid solution: 0.176 M

We can calculate the number of moles of phosphoric acid using the formula:

moles = concentration x volume (in liters)

First, we need to convert the volume from milliliters to liters:

13.8 mL x (1 L / 1000 mL) = 0.0138 L

Now, we can calculate the number of moles of phosphoric acid:

moles = 0.176 M x 0.0138 L = 0.00242 mol

Calculating the Number of Moles of Sodium Hydroxide Required

Since the reaction is a 1:3 ratio, we need to calculate the number of moles of sodium hydroxide required to react with the phosphoric acid. We can do this by multiplying the number of moles of phosphoric acid by 3:

moles of NaOH = 3 x moles of H3PO4 = 3 x 0.00242 mol = 0.00726 mol

Calculating the Volume of Sodium Hydroxide Solution Required

Now that we know the number of moles of sodium hydroxide required, we can calculate the volume of the solution needed to reach the equivalence point. We are given the concentration of the sodium hydroxide solution:

Concentration of sodium hydroxide solution: 0.110 M

We can calculate the volume of the solution required using the formula:

volume = moles / concentration

First, we need to convert the concentration from moles per liter to moles per milliliter:

0.110 M = 0.110 mol/L = 0.110 mol/1000 mL = 0.00011 mol/mL

Now, we can calculate the volume of the solution required:

volume = moles / concentration = 0.00726 mol / 0.00011 mol/mL = 66.0 mL

In this article, we have calculated the volume of base required to reach the equivalence point in a titration reaction involving phosphoric acid and sodium hydroxide. We have used the given information to calculate the number of moles of phosphoric acid and sodium hydroxide required, and then used these values to calculate the volume of the sodium hydroxide solution needed to reach the equivalence point. The calculated volume is 66.0 mL.

Chemistry: An Atoms First Approach, by Steven S. Zumdahl
General Chemistry: Principles and Modern Applications, by Linus Pauling

Titration: A Comprehensive Guide
Phosphoric Acid: Properties and Uses
Sodium Hydroxide: Properties and Uses
A Comprehensive Guide to Titration: Q&A

Titration is a fundamental technique in chemistry used to determine the concentration of a substance in a solution. In our previous article, we explored the concept of titration and calculated the volume of base required to reach the equivalence point in a specific titration reaction. In this article, we will answer some frequently asked questions about titration and provide additional information to help you better understand this technique.

Q: What is the purpose of titration?

A: The purpose of titration is to determine the concentration of a substance in a solution. It involves the reaction of a known concentration of one substance (the titrant) with a solution of unknown concentration (the analyte) until the reaction is complete, known as the equivalence point.

Q: What are the different types of titration?

A: There are several types of titration, including:

Acid-base titration: This type of titration involves the reaction of an acid with a base.
Redox titration: This type of titration involves the reaction of a reducing agent with an oxidizing agent.
Complexation titration: This type of titration involves the reaction of a metal ion with a complexing agent.
Precipitation titration: This type of titration involves the reaction of a metal ion with a precipitating agent.

Q: What are the advantages of titration?

A: The advantages of titration include:

High accuracy: Titration can provide highly accurate results.
High precision: Titration can provide highly precise results.
Simple equipment: Titration can be performed with simple equipment.
Low cost: Titration can be performed at a low cost.

Q: What are the limitations of titration?

A: The limitations of titration include:

Limited range: Titration is typically limited to a specific range of concentrations.
Limited accuracy: Titration may not provide accurate results for very low or very high concentrations.
Limited precision: Titration may not provide precise results for very low or very high concentrations.

Q: How do I choose the right titrant for my titration?

A: To choose the right titrant for your titration, you should consider the following factors:

The concentration of the analyte: Choose a titrant with a concentration that is close to the concentration of the analyte.
The reaction mechanism: Choose a titrant that reacts with the analyte in a predictable and reliable manner.
The availability of the titrant: Choose a titrant that is readily available and easy to obtain.

Q: How do I perform a titration?

A: To perform a titration, you should follow these steps:

Prepare the titrant and the analyte solutions.
Add the titrant to the analyte solution in small increments.
Monitor the reaction using a pH meter or a colorimetric indicator.
Record the volume of titrant added at the equivalence point.
Calculate the concentration of the analyte using the titration data.

Q: What are some common errors in titration?

A: Some common errors in titration include:

Incorrect concentration of the titrant or the analyte.
Incorrect volume of titrant added.
Incorrect pH or colorimetric indicator used.
Incorrect calculation of the concentration of the analyte.

In this article, we have answered some frequently asked questions about titration and provided additional information to help you better understand this technique. We hope that this information has been helpful in your understanding of titration and that you will be able to apply this knowledge in your future experiments.

Chemistry: An Atoms First Approach, by Steven S. Zumdahl
General Chemistry: Principles and Modern Applications, by Linus Pauling

Titration: A Comprehensive Guide
Phosphoric Acid: Properties and Uses
Sodium Hydroxide: Properties and Uses