Calcium Hydroxide and Carbon Dioxide (Limewater Test)
Ca(OH)2 + CO2 → CaCO3 + H2O
Overview
Calcium hydroxide solution (limewater) turns milky white when carbon dioxide is bubbled through it, due to the formation of insoluble calcium carbonate particles. This is the classic test for carbon dioxide gas. With excess CO2, the milkiness disappears as soluble calcium bicarbonate forms.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Calcium Hydroxide Ca(OH)₂ | 1 | (aq) |
| Reactant | Carbon Dioxide CO₂ | 1 | (g) |
| Product | Calcium Carbonate CaCO₃ | 1 | (s) |
| Product | Water H₂O | 1 | (l) |
Everyday Example
The limewater test is taught in every introductory chemistry course as the standard qualitative test for carbon dioxide gas.
Industrial Importance
This reaction is used in flue gas desulfurization, carbon capture, and in the production of precipitated calcium carbonate for paper and paint industries.
Properties
- Type
- Double Replacement
- Reversible
- No
- Energy
- Exothermic
- ΔH
- -113.0 kJ/mol
Related Reactions
Aluminum Hydroxide and Hydrochloric Acid
Ammonia and Hydrochloric Acid (White Smoke)
Barium Chloride and Sodium Sulfate Precipitation
Calcium Carbonate and Hydrochloric Acid
Calcium Chloride and Sodium Carbonate
Calcium Hydroxide and Sulfuric Acid
Copper(II) Sulfate and Sodium Hydroxide
Iron(III) Chloride and Sodium Hydroxide
Lead Nitrate and Potassium Iodide (Golden Rain)
Magnesium Hydroxide and Hydrochloric Acid (Antacid)
Frequently Asked Questions
What is the equation for Calcium Hydroxide and Carbon Dioxide (Limewater Test)?
The balanced equation is: Ca(OH)₂ + CO₂ → CaCO₃ + H₂O.
What type of reaction is Calcium Hydroxide and Carbon Dioxide (Limewater Test)?
Calcium Hydroxide and Carbon Dioxide (Limewater Test) is a double replacement reaction.
Is Calcium Hydroxide and Carbon Dioxide (Limewater Test) exothermic or endothermic?
Calcium Hydroxide and Carbon Dioxide (Limewater Test) is exothermic (releases energy). The enthalpy change (ΔH) is -113.0 kJ/mol.