Cupric chloride (CuCl₂) itself doesn't burn blue. It's actually a solid at room temperature and doesn't have a characteristic flame color.

The blue color you might be referring to is likely related to the following:

* Copper ions in flames: When cupric chloride is heated in a flame, the copper ions (Cu²⁺) in the compound get excited. As they transition back to their ground state, they emit light in the blue-green region of the spectrum, which is why you see a blue-green flame.

* Copper salts in solutions: Cupric chloride solutions can appear blue-green due to the absorption and reflection of light by the hydrated copper ions.

Here's a breakdown:

1. Flame Tests: In a flame test, a small amount of the compound is placed on a wire loop and heated in a flame. The flame color is then observed. Cupric chloride gives a blue-green flame due to the copper ions.

2. Solutions: Cupric chloride dissolves in water to form a blue-green solution due to the complex formation of the copper ions with water molecules.

Important Note: While cupric chloride can be used in flame tests, it is not flammable itself. It's the excited copper ions that cause the blue-green light emission.