Vernier Software & Technology

# Oxidation-Reduction Titrations

## Introduction

A titration, as you recall, is a convenient method of learning more about a solution by reacting it with a second solution of known molar concentration. There are a number of ways to measure the progress of a titration. In this experiment, you will use an ORP (Oxidation-Reduction Potential) Sensor to measure the electrical potential of the reaction being studied in a titration.

You will be titrating commercial bleach with hydrogen peroxide of known molarity in order to determine the molarity of the bleach sample. The reaction being studied can be represented as follows:

${\text{NaOCl(aq) + }}{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}{\text{(aq)}} \to {\text{NaCl(aq) + }}{{\text{H}}_{\text{2}}}{\text{O(l) + }}{{\text{O}}_{\text{2}}}{\text{(g)}}$

where NaOCl is sodium hypochlorite, a representative component of bleach, and H2O2 is the formula for hydrogen peroxide. The products are sodium chloride, water, and oxygen. Your sample of H2O2 will come from a bottle of ordinary, over-the-counter hydrogen peroxide purchased at a grocery or a drug store. The concentration of this product is labeled as 3% mass/volume, which is ~0.88 M.

## Objectives

In the Preliminary Activity, you will be titrating commercial bleach with hydrogen peroxide of known molarity in order to determine the molarity of the bleach sample.

After completing the Preliminary Activity, you will first use reference sources to find out more about oxidation, reduction, and oxidation-reduction titrations before you choose and investigate a researchable question using oxidation-reduction 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 19 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.