Question:
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Updated On: Jan 13, 2026
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Solution and Explanation
Decomposition reactions are those in which a compound breaks down to form two or more substances. These reactions require a source of energy to proceed. Thus, they are the exact opposite of combination reactions in which two or more substances combine to give a new substance with the release of energy.
Decomposition reaction: AB + Energy \(→\) A + B
2H2O(l) \(\xrightarrow{Electrolysis}\) 2H2(g) + O2(g)
Combination reaction: A + B \(→\) AB + Energy
2H2(s) + O2(g) \(→\) 2H2O(l) + Energy
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