Reaction of Carbon Dioxide with Lime Water
When carbon dioxide gas (\(CO_2\)) is bubbled through lime water, a specific chemical reaction occurs. Lime water is the common name for a clear, aqueous solution of calcium hydroxide, which has the chemical formula \(Ca(OH)_2\).
Understanding the Chemistry of Lime Water and \(CO_2\)
The reaction involves the interaction between the dissolved calcium hydroxide in lime water and the incoming carbon dioxide gas. This process results in the formation of calcium carbonate (\(CaCO_3\)), which is insoluble in water, and water (\(H_2O\)).
The specific chemical equation representing this transformation is:
\(Ca(OH)_2(aq) + CO_2(g) \rightarrow CaCO_3(s) + H_2O(l)\)
Breakdown of the Reaction:
- Reactants: Calcium hydroxide solution (\(Ca(OH)_2(aq)\)) and Carbon dioxide gas (\(CO_2(g)\)).
- Products: Calcium carbonate solid precipitate (\(CaCO_3(s)\)) and Water (\(H_2O(l)\)).
The formation of the solid calcium carbonate (\(CaCO_3\)) is observed as a white precipitate, causing the lime water to turn milky or cloudy. This observation is a key characteristic test for carbon dioxide gas.
Evaluating Alternative Reactions
Let's examine the other options to understand why they don't represent the primary reaction:
- Option 1: \(CaCO_3 + H_2O + CO_2 \rightarrow Ca(HCO_3)_2\)
This equation describes the reaction that happens when excess carbon dioxide is passed through the lime water *after* the initial formation of calcium carbonate. The calcium carbonate reacts further to form soluble calcium bicarbonate (\(Ca(HCO_3)_2\)), and the milky appearance disappears. This is a subsequent step, not the initial reaction. - Option 3: \(CaO + CO_2 \rightarrow CaCO_3\)
This reaction involves calcium oxide (quicklime, CaO) reacting with carbon dioxide. However, lime water is specifically a solution of calcium *hydroxide* (\(Ca(OH)_2\)), not calcium oxide. - Option 4: \(CaCl_2 + H_2O + CO_2 \rightarrow CaCO_3 + 2HCl\)
This reaction is chemically incorrect and does not represent the process of passing carbon dioxide through lime water. Calcium chloride (\(CaCl_2\)) does not react in this manner.
The initial and defining reaction when carbon dioxide gas is introduced to lime water is the precipitation of calcium carbonate.
Similar Questions
- The chemical reaction:
\(2AgCl (s) \to 2Ag (s) + Cl_2 (g)\)
takes place Which one among the following is an example of oxidation reaction?
Which one among the following is an example of chemical change?
- Which one of the following is NOT a chemical change?
- Which one of the following is an endothermic reaction?
Match List I with List II and select the answer using the code given below the Lists:
List I
(Reaction)List II
(Type)A. \(CaO (s) + H_2O (l) \rightarrow Ca(OH)_2 (aq)\) 1. Single displacement B. \(CaCO_3 (s) \rightarrow CaO (s) + CO_2 (g)\) 2. Double displacement C. \(Pb (s) + CuCl_2 (aq) \rightarrow PbCl_2 (aq) + Cu (s)\) 3. Combination D. \(Na_2SO_4 (aq) + BaCl_2 (aq) \rightarrow BaSO_4 (s) + 2NaCl (aq)\) 4. Decomposition
Code:
Important Questions from Chemical Reactions
Which of the following is/are the example/examples of chemical change?
(1) Crystallization of sodium chloride
(2) Melting of ice
(3) Souring of milk
Select the correct answer using the code given below.
Aspartame is an artificial sweetener sold in the market. It consists of amino acids and provides calories like other amino acids. Yet, it is used as a low-calorie sweetening agent in food items. What is the basis of this use?
Photochemical smog is a resultant of the reaction among
- Phosphorus is kept in water because
What is the product formed when sodium bicarbonate is heated strongly?
