Understanding Chemical Reaction Types

This question requires matching specific chemical reactions provided in List I with their corresponding types listed in List II. We need to analyze each reaction to determine its type.

Analyzing Reaction A: Combination

Reaction A is given as: \(CaO (s) + H_2O (l) \rightarrow Ca(OH)_2 (aq)\) In this reaction, two substances, solid calcium oxide (CaO) and liquid water (\(H_2O\)), combine to form a single product, aqueous calcium hydroxide (\(Ca(OH)_2\)). This type of reaction, where two or more reactants combine to form a single product, is known as a Combination reaction. Therefore, reaction A matches with type 3.

Identifying Reaction B: Decomposition

Reaction B is given as: \(CaCO_3 (s) \rightarrow CaO (s) + CO_2 (g)\) Here, a single compound, solid calcium carbonate (\(CaCO_3\)), breaks down into two simpler substances, solid calcium oxide (CaO) and carbon dioxide gas (\(CO_2\)). This process, where a compound decomposes into simpler substances, is called a Decomposition reaction. Thus, reaction B matches with type 4.

Classifying Reaction C: Single Displacement

Reaction C is presented as: \(Pb (s) + CuCl_2 (aq) \rightarrow PbCl_2 (aq) + Cu (s)\) In this reaction, solid lead (Pb) reacts with aqueous copper(II) chloride (\(CuCl_2\)). The lead displaces copper from the copper(II) chloride compound, forming aqueous lead(II) chloride (\(PbCl_2\)) and solid copper (Cu). This is a characteristic of a Single displacement reaction, where one element replaces another element in a compound. So, reaction C matches with type 1.

Determining Reaction D: Double Displacement

Reaction D is: \(Na_2SO_4 (aq) + BaCl_2 (aq) \rightarrow BaSO_4 (s) + 2NaCl (aq)\) This reaction involves two aqueous ionic compounds, sodium sulfate (\(Na_2SO_4\)) and barium chloride (\(BaCl_2\)). They react to form a precipitate of barium sulfate (\(BaSO_4\)) and aqueous sodium chloride (NaCl). The positive ions (\(Na^+\) and \(Ba^{2+}\)) and negative ions (\(SO_4^{2-}\) and \(Cl^-\)) effectively swap partners. This exchange of ions between two compounds is known as a Double displacement reaction. Therefore, reaction D matches with type 2.

Matching Lists and Selecting the Code

Based on the analysis above, the correct matches are:

• A matches with 3 (Combination)
• B matches with 4 (Decomposition)
• C matches with 1 (Single displacement)
• D matches with 2 (Double displacement)

The code representing this match (A:3, B:4, C:1, D:2) is 3, 4, 1, 2.

Now, let's compare this code with the given options:

The code 3, 4, 1, 2 corresponds to option (c).