Vernier Software and Technology
Vernier Software & Technology

Investigating Indicators

Figure from experiment 11 from Advanced Chemistry with Vernier

Introduction

An indicator solution does what its name suggests – it indicates. In chemistry, a common use of an indicator is to signal the equivalence point of a reaction between an acid and a base. Generally, an indicator is itself a weak organic acid or a blend of weak organic acids. The indicator establishes equilibrium in aqueous solution, which is shifted according to LeChatelier’s principle as the solution changes in pH. The indicator is one color in the presence of a range of concentrations of H+ or OH ions, and another color when the acidity changes. Knowing when an indicator will change color helps you determine the precise equivalence point of an acid-base reaction. This knowledge is also important as you select the proper indicator for a given reaction.

Objectives

In this experiment, you will

  • Conduct strong acid-strong base titrations using solutions of hydrochloric acid and sodium hydroxide, and three different indicator solutions.
  • Select the proper indicator to use with a titration involving a weak acid or a weak base, based on your observations and measurements.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Option 1

Option 2

Additional Requirements

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

Standards Correlations

See all standards correlations for Advanced Chemistry with Vernier »

Experiment 11 from Advanced Chemistry with Vernier Lab Book

<i>Advanced Chemistry with Vernier</i> book cover

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.

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