Vernier Software & Technology

# Acid-Base Titrations

## Introduction

A titration is a process used to determine the volume of a solution needed to react with a given amount of another substance. When titrating a solution of the strong acid hydrochloric acid, HCl, with a solution of the strong base sodium hydroxide, NaOH, the hydrogen ions from the HCl react with hydroxide ions from the NaOH in a one-to-one ratio to produce water in the overall reaction:

${{\text{H}}^{\text{ + }}}{\text{(aq) + C}}{{\text{l}}^ - }{\text{(aq) + N}}{{\text{a}}^{\text{ + }}}{\text{(aq) + O}}{{\text{H}}^ - }{\text{(aq)}} \to {{\text{H}}_{\text{2}}}{\text{O(l) + N}}{{\text{a}}^{\text{ + }}}{\text{(aq) + C}}{{\text{l}}^ - }{\text{(aq)}}$

When an HCl solution is titrated with an NaOH solution, the pH of the acidic solution is initially low. As base is added, the change in pH is quite gradual until close to the equivalence point, when equimolar amounts of acid and base have been mixed. Near the equivalence point, the pH increases very rapidly. The change in pH then becomes more gradual again, before leveling off with the addition of excess base.

## Objectives

In the Preliminary Activity, you will titrate a solution of the strong acid hydrochloric acid, HCl, with a solution of the strong base sodium hydroxide, NaOH. The concentration of the NaOH solution is given and you will determine the unknown concentration of the HCl.

After completing the Preliminary Activity, you will first use reference sources to find out more about acids, bases, and acid-base titrations before you choose and investigate a researchable question utilizing acid-base titrations.

## Sensors and Equipment

This investigation features the following Vernier sensors and equipment.

### Option 2

You may also need an interface and software for data collection. What do I need for data collection?

## Investigating Chemistry through Inquiry

See other experiments from the lab book.

 1 Physical Properties of Water 2 Baking Soda and Vinegar Investigations 3 An Investigation of Urea-Containing Cold Packs 4 Conductivity of Aqueous Solutions 5 Identifying a Pure Substance 6 Investigating the Energy Content of Foods 7 Investigating the Energy Content of Fuels 8 Evaporation and Intermolecular Attractions 9 Enthalpy Changes 10 Reaction Stoichiometry 11 Beer's Law Investigations 12 Colligative Properties of Solutions 13 Long Term Water Monitoring 14 Vapor Pressure and Heat of Vaporization Investigations 15 Acid-Base Properties of Household Products 16 The Effect of Acid Deposition on Aqueous Systems 17 Acid-Base Titrations 18 Conductimetric Titrations 19 Oxidation-Reduction Titrations 20 Investigating Voltaic Cells 21 Baking Soda and Vinegar Investigations Revisited 22 Reaction Rates 23 Enzyme Activity 24 Sugar Fermentation by Yeast 25 Nuclear Radiation

### Investigation 17 from Investigating Chemistry through Inquiry Lab Book

#### Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.