Complete the reactions
(i) `CH_(3)CH_(3) +HNO_(3) overset("vapour phase")to `
(ii) `CH_(4)+ O_(2) underset(723-773k)overset("Copper tube")to `
(iii) `C_(2)H_(5)COONa+ NaOH overset(CaO)to`

Explanation

Let's solve the given reactions step by step.

### Reaction (i):
**Given:**
\[ \text{CH}_3\text{CH}_3 + \text{HNO}_3 \overset{\text{vapour phase}}{\rightarrow} \]

**Step 1:** Identify the reactants.
We have ethane (\( \text{CH}_3\text{CH}_3 \)) and nitric acid (\( \text{HNO}_3 \)).
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