Preparation and testing of carbon dioxide
React marble chips with dilute hydrochloric acid and test the gas given off.
Objectives
- Prepare carbon dioxide from a carbonate and an acid.
- Identify carbon dioxide by its tests.
Theory
Carbonates react with acids to give a salt, water and carbon dioxide. Carbon dioxide is denser than air, does not support burning and turns limewater milky by forming insoluble calcium carbonate.
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂↑
Procedure
- Put on your safety goggles and lab coat.
- Place a conical flask on the bench.
- Add about 10 g of marble chips.
- Add about 50 mL of dilute hydrochloric acid.
- Observe the effervescence.
- Test the gas with a burning splint.
- Test the gas with limewater.
Precautions
- Add the acid slowly to avoid frothing over.
- Subject
- Chemistry
- Grade
- 9–10
- Chapter
- Some Gases (Nepal National Curriculum (CDC), grade 9)
- Difficulty
- Easy
- Duration
- 15 min
- Safety level
- Low
- Version
- 1.0
Apparatus
- Conical flask (250 mL)
Chemicals
- Calcium carbonate (marble chips) CaCO₃
- Dilute hydrochloric acid HCl Corrosive
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