Vernier Software & Technology

# Conductimetric Titrations

## Introduction

There are a number of ways to investigate a chemical reaction. Measuring temperature change, pressure change, pH change, and/or conductivity change are some of the ways. A titration is a process used to determine the volume of a solution needed to react with a given amount of another substance. You have probably done pH titrations in other experiments; now you will be performing conductivity titrations. 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. 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:

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

## Objectives

You will determine the volume of NaOH titrant used at the equivalence point using the intersection of the linear fits of the two branches of the resulting curve. The volume of NaOH titrant used at the equivalence point will be used to determine the molarity of the HCl.

After completing the Preliminary Activity, you will first use reference sources to find out more about conductimetric titrations before you choose and investigate a researchable question involving conductimetric 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 18 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.