Experiment 34

Objective

To identify the presence of a barium salt in a supplied sample through the reaction with dilute acetic acid.

Introduction

Barium salts are typically insoluble and often produce a white precipitate in solution. When a barium salt is heated in the presence of dilute acetic acid, it reacts to form a colorless solution, releasing carbon dioxide gas as a byproduct.

Chemical Reaction:

BaCO₃ + 2CH₃COOH → (CH₃COO)₂Ba + CO₂ + H₂O

Materials

Chemicals

●      Barium chloride (BaCl₂)

●      Acetic acid (CH₃COOH)

●      Distilled water

Apparatus:

●      Test tube

●      Test tube holder

●      Bunsen burner

Reagents:

●      Prepare a 5% acetic acid solution in a 250 ml beaker.

Procedure

1.    Sample Preparation: Place 5-6 ml of the barium salt solution in a test tube.

2.    Heating Step: Heat the sample in hot water.

3.    Acetic Acid Addition: Add 7-8 ml of 5% acetic acid to the heated sample.

4.    Observation: Observe any changes in the reaction, focusing on color and solubility.

Observations

●      When heated in the presence of acetic acid, the initially white precipitate dissolves, resulting in a colorless solution, confirming the presence of a barium salt.

Questions

1.    What is a barium salt?

2.    How is a barium salt identified?

3.    What reagent is required for the barium test?