Vernier Software & Technology

# Conductimetric Titration and Gravimetric Determination of a Precipitate

## Introduction

In this experiment, you will monitor conductivity during the reaction between sulfuric acid, H2SO4, and barium hydroxide, Ba(OH)2, in order to determine the equivalence point. From this information, you can find the concentration of the Ba(OH)2 solution. The reaction between sulfuric acid and barium hydroxide yields an insoluble product, barium sulfate, and water, as shown in the reaction equation below.

${\text{B}}{{\text{a}}^{{\text{2}} + }}\left( {{\text{aq}}} \right) + {\text{2 O}}{{\text{H}}^-}\left( {{\text{aq}}} \right) + {\text{2 }}{{\text{H}}^ + }\left( {{\text{aq}}} \right) + {\text{S}}{{\text{O}}_{\text{4}}}^{{\text{2}}-}\left( {{\text{aq}}} \right) \to {\text{BaS}}{{\text{O}}_{\text{4}}}\left( {\text{s}} \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( {\text{l}} \right)$

In this reaction, the total number of dissociated ions in solution is reduced dramatically during the reaction as a precipitate is formed. As 0.100 M H2SO4 is slowly added to Ba(OH)2 of unknown concentration, changes in the conductivity of the solution will be monitored using a Conductivity Probe. When the probe is placed in a solution that contains ions, and thus has the ability to conduct electricity, an electrical circuit is completed across the electrodes that are located on either side of the hole near the bottom of the probe body. This results in a conductivity value that can be read by the interface. The unit of conductivity used in this experiment is the microsiemens/cm, or µS/cm.

In addition, you will capture the precipitate, and measure its mass. You will have two methods, therefore, of calculating the molar concentration of a barium hydroxide solution that is titrated with a sulfuric acid solution of known concentration.

## Objectives

In this experiment, you will

• Measure the conductivity of the reaction between sulfuric acid and barium hydroxide.
• Use conductivity values as a means of determining the equivalence point of the reaction.
• Measure the mass of a product of the reaction as a means of determining the equivalence point of the reaction gravimetrically.
• Calculate the molar concentration of a barium hydroxide solution.

## Sensors and Equipment

This experiment 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?

## Advanced Chemistry with Vernier

See other experiments from the lab book.

 1 The Determination of a Chemical Formula 2 The Determination of the Percent Water in a Compound 3 The Molar Mass of a Volatile Liquid 4 Using Freezing-Point Depression to Find Molecular Weight 5 The Molar Volume of a Gas 6 Standardizing a Solution of Sodium Hydroxide 7 Acid-Base Titration 8 An Oxidation-Reduction Titration: The Reaction of Fe2+ and Ce4+ 9 Determining the Mole Ratios in a Chemical Reaction 10 The Determination of an Equilibrium Constant 11 Investigating Indicators 12 The Decomposition of Hydrogen Peroxide 13 Determining the Enthalpy of a Chemical Reaction 14A Separation and Qualitative Analysis of Cations 14B Separation and Qualitative Analysis of Anions 15A The Synthesis of Alum 15B The Analysis of Alum 16 Conductimetric Titration and Gravimetric Determination of a Precipitate 17 Determining the Concentration of a Solution: Beer's Law 18 Liquid Chromatography 19 Buffers 20 Electrochemistry: Voltaic Cells 21 Electroplating 22 The Synthesis and Analysis of Aspirin 23 Determining the Ksp of Calcium Hydroxide 24 Determining Ka by the Half-Titration of a Weak Acid 25 The Rate and Order of a Chemical Reaction 26 The Enthalpy of Neutralization of Phosphoric Acid 27 α, β, and γ 28 Radiation Shielding 29 The Base Hydrolysis of Ethyl Acetate 30 Exploring the Properties of Gases 31 Determining Avogadro's Number 32 Potentiometric Titration of Hydrogen Peroxide 33 Determining the Half-Life of an Isotope 34 Vapor Pressure and Heat of Vaporization 35 Rate Determination and Activation Energy

### Experiment 16 from Advanced Chemistry with Vernier 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.

Dev Reference: VST0017