Chemical Analysis: Identification of Common Gases

Chemical Analysis: Identification of Common Gases

Identification of Common Gases

• In chemical reactions, gases may be produced as products and need to be identified. There are specific tests for different gases to confirm their presence.

Hydrogen Gas

• Hydrogen gas can be identified using the ‘pop’ test.
• In this test, a lighted splint is brought near the opening of a test tube containing the gas.
• Hydrogen will ignite with a ‘pop’ sound, confirming its presence.

Oxygen Gas

• Oxygen can be identified using a ‘glowing splint’ test.
• A glowing splint will relight when placed in a test tube of oxygen gas, indicating its presence.

Carbon Dioxide Gas

• Carbon dioxide can be tested by passing the gas through limewater.
• If the limewater turns cloudy or milky, it indicates the presence of carbon dioxide gas.

Chlorine Gas

• Chlorine gas can be identified by its effect on damp blue litmus paper.
• The litmus paper turns red and then white, indicating the presence of chlorine.

Ammonia Gas

• Ammonia gas has a distinctive pungent smell.
• It also turns damp red litmus paper blue, confirming the presence of ammonia.

Sulfur Dioxide Gas

• Sulfur dioxide bleaches damp litmus paper. Initially, the paper turns red because of the acid nature of sulfur dioxide and then becomes white, indicating the presence of this sulfur dioxide.

Safety Precautions

• When carrying out these tests, take proper safety precautions to protect your hands and eyes and dispose of any chemical waste safely.
• Care should be taken with the gases since they are all potentially hazardous. Always conduct these experiments in a well-ventilated space under proper supervision.

These tests are crucial for the identification of gases in a chemical analysis and understanding these tests can form the foundational basis of higher-level chemistry.