02 Ethyne Gas

Summary

This educational video demonstrates the preparation of ethyne gas in a laboratory setting. The process begins with calcium carbide and deionized water in a flask, generating ethyne gas and calcium oxide. To purify the gas, copper sulfate and sulfuric acid are used. The gas is collected over water and tested for unsaturation using potassium permanganate and bromine water, which decolorize in the presence of ethyne. The video concludes with a flame test to confirm the presence of ethyne, showcasing a successful experiment.

Takeaways

• 🔬 The experiment demonstrates the preparation of ethyne gas, which consists of two carbon atoms triple-bonded with two hydrogens.
• 🧪 Calcium carbide reacts with water to produce ethyne gas and calcium oxide as a by-product.
• 💧 Deionized water is used in the reaction to ensure purity of the ethyne gas produced.
• 🌐 The setup includes a doctor flask, dropping funnel, and a gas collection jar to facilitate the reaction and collection of ethyne gas.
• 🔄 Copper sulfate and sulfuric acid are used to remove impurities from the ethyne gas.
• 🔬 The presence of an unsaturated compound is confirmed through the decolorization of potassium permanganate and bromine water.
• 🔥 A flame test is conducted to definitively test for the presence of ethyne gas, which burns with a distinctive flame.
• 🧑‍🔬 Safety precautions are emphasized, such as wearing a lab coat and conducting the experiment in a fume hood.
• ⏱️ The reaction is initiated by adding water to the calcium carbide in the flask, and the gas is collected once the air is displaced.
• 📝 The script provides a detailed step-by-step guide for conducting the experiment, including the use of specific chemicals and apparatus.

Q & A

What is the main objective of the practical described in the script?

The main objective of the practical is to prepare ethyne gas.

What is the molecular structure of ethyne gas?

Ethyne gas has a molecular structure with two carbons bonded by a triple bond and each carbon is also bonded to a hydrogen atom.

What are the chemicals used to produce ethyne gas in the practical?

Calcium carbide and deionized water are used to produce ethyne gas.

Why is copper sulfate mixed with sulfuric acid used in the preparation?

Copper sulfate mixed with sulfuric acid is used to remove impurities from the ethyne gas.

What is the purpose of the beehive in the apparatus setup?

The beehive is used to displace water and collect the ethyne gas.

How is the ethyne gas collected in the practical?

Ethyne gas is collected by filling glass jars with water, inverting them in a water trough, and then connecting them to the gas outlet of the reaction flask.

What is the purpose of the flame test in the practical?

The flame test is used to confirm the presence of ethyne gas by observing the color of the flame.

What is the significance of the decolorization of bromine water in the practical?

The decolorization of bromine water indicates the presence of an unsaturated compound, as ethyne gas reacts with bromine, causing the solution to lose its color.

Why is it important to remove the displaced air before collecting ethyne gas?

It is important to remove the displaced air before collecting ethyne gas to ensure that the collected gas sample is pure and not contaminated with air.

How is the reaction initiated between calcium carbide and water?

The reaction is initiated by allowing water to drop onto the calcium carbide in the flask, which produces ethyne gas and calcium oxide as a by-product.

What safety precautions are mentioned in the script during the practical?

The script mentions wearing a lab coat and conducting the flame test in a fume cupboard as safety precautions.