Question

Write the laboratory preparation of ethyne gas in brief.

Short answer

Question: Briefly explain the laboratory preparation of ethyne gas. Answer: The laboratory preparation of ethyne gas involves a reaction between calcium carbide (CaC2) and water (H2O), which produces ethyne (C2H2) and calcium hydroxide (Ca(OH)2). The process includes setting up a dropping funnel connected to a gas collection apparatus, adding calcium carbide to the funnel, and slowly introducing water drop by drop to control the reaction rate. The ethyne gas released is then collected by displacing air in the container. Finally, the presence of ethyne is confirmed by creating a small explosion or popping sound when a source of ignition is brought close to the container's mouth.

Step-by-step solution

Materials and equipment required

To prepare ethyne gas in a laboratory, the following materials and equipment are needed: 1. Calcium carbide (CaC2) 2. Water 3. A dropping funnel 4. A gas collection apparatus 5. A source of ignition (e.g., a bunsen burner or a lighter)

Set up the apparatus

Arrange the dropping funnel with its opening connected to a gas collection apparatus (such as a test tube or an inverted graduated cylinder). The delivery tube of the apparatus should be connected to the dropping funnel so that the gases produced can be collected in the desired vessel.

Add calcium carbide

Place a small amount of calcium carbide (CaC2) into the dropping funnel.

Add water

Slowly add water (H2O) into the funnel containing calcium carbide. The water should be added drop by drop to control the reaction rate and ensure the safe production of ethyne gas.

Observe the reaction

The reaction between calcium carbide and water generates ethyne (C2H2) gas and calcium hydroxide (Ca(OH)2) as a byproduct: CaC2 + 2H2O -> C2H2 + Ca(OH)2 The ethyne gas will be released through the delivery tube and can be collected in the gas collection apparatus.

Collect the ethyne gas

Collect the ethyne gas in the gas collection apparatus by allowing it to displace the air in the container. Ensure that the gas collection process is done carefully to avoid any accidents.

Test the ethyne gas

Once enough ethyne gas has been collected, test the gas to confirm its presence. This can be done by bringing a source of ignition near the mouth of the gas collection container, which should cause a small explosion or a loud popping sound.