On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed.
Write a balanced chemical equation of the reaction.

Explanation

To write the balanced chemical equation for the decomposition of copper (II) nitrate upon heating, follow these steps:

### Step 1: Identify the Reactants and Products
The reactant is copper (II) nitrate, which has the chemical formula \( \text{Cu(NO}_3\text{)}_2 \). Upon heating, it decomposes to form:
- Copper oxide (black), with the formula \( \text{CuO} \)
- Oxygen gas, with the formula \( \text{O}_2 \)
- A brown gas, which is nitrogen dioxide, with the formula \( \text{NO}_2 \)

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