One mole of ethyne undergoes combustion giving 2 moles `CO_2,` ______ moles `H_2O`. (one/four)

Explanation

To solve the question, we need to understand the combustion reaction of ethyne (C2H2). The combustion of ethyne can be represented by the following balanced chemical equation:

1. **Write the balanced equation for the combustion of ethyne:**
\[ C_2H_2 + \frac{5}{2} O_2 \rightarrow 2 CO_2 + H_2O \]

2. **Identify the products formed:**
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