What kind of reaction occurs between CuCl₂ and Na₂S?

The reaction between copper(II) chloride (CuCl₂) and sodium sulfide (Na₂S) is a double displacement reaction, also known as a precipitation reaction. In this process, the ions in the two compounds exchange partners. The reaction produces copper(II) sulfide (CuS) as a precipitate and sodium chloride (NaCl) as a soluble product in the solution. The balanced chemical equation is:

CuCl2+Na2S→CuS↓+2NaClCuCl2​+Na2​S→CuS↓+2NaCl

Here, CuS is insoluble in water and appears as a black solid, while NaCl remains dissolved. This reaction demonstrates the principle of solubility rules and ion exchange in aqueous solutions.