Which of the following is best described as a decomposition reaction?
[tex]HCl + NaHCO _3 \rightarrow H _2 O + CO _2+ NaCl[/tex]
[tex]2 Na + Cl _2 \rightarrow 2 NaCl[/tex]
[tex]2 HgO \rightarrow 2 Hg + O _2[/tex]
[tex]AgNO _3+ NaCl \rightarrow AgCl + NaNO _3[/tex]
Answer (2)
A decomposition reaction involves a single compound breaking down into simpler substances.
Examine each reaction to see if it fits the definition of a decomposition reaction.
2 H g O → 2 H g + O 2 is the only reaction where a single compound breaks down into simpler substances.
The decomposition reaction is: 2 H g O → 2 H g + O 2
Explanation
Understanding Decomposition Reactions A decomposition reaction is a chemical reaction where a single compound breaks down into two or more simpler substances. We need to identify which of the given reactions fits this description.
Analyzing Each Reaction Let's examine each reaction:
H Cl + N a H C O 3 → H 2 O + C O 2 + N a Cl : This reaction involves two reactants combining to form multiple products. This is not a decomposition reaction.
2 N a + C l 2 → 2 N a Cl : This reaction involves two elements combining to form a single compound. This is a synthesis reaction, not a decomposition reaction.
2 H g O → 2 H g + O 2 : This reaction involves a single compound ( H g O ) breaking down into two simpler substances ( H g and O 2 ). This is a decomposition reaction.
A g N O 3 + N a Cl → A g Cl + N a N O 3 : This reaction involves two compounds exchanging ions. This is a double displacement reaction, not a decomposition reaction.
Identifying the Decomposition Reaction Based on the analysis, the reaction 2 H g O → 2 H g + O 2 is the only one that fits the definition of a decomposition reaction.
Final Answer Therefore, the best description of a decomposition reaction among the given options is: 2 H g O → 2 H g + O 2
Examples
Decomposition reactions are commonly used in various industrial processes, such as the extraction of metals from their ores. For example, heating metal carbonates like calcium carbonate ( C a C O 3 ) leads to its decomposition into calcium oxide ( C a O ) and carbon dioxide ( C O 2 ), which is a crucial step in the production of cement. This process can be represented as: C a C O 3 → C a O + C O 2 . Understanding decomposition reactions is essential for optimizing these processes and developing new technologies.
The best description of a decomposition reaction among the given options is 2 H g O → 2 H g + O 2 as it involves a single compound breaking down into simpler substances. The other reactions are not classified as decomposition. Understanding these reactions is essential in the study of chemistry.
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