Which of the following statements regarding copper salts is not true?

Options

A. Copper (I) disproportionates into Cu and Cu (II) in aqueous solution
B. Copper (I) can be stabilized by the formation of insoluble complex compounds such as `CuCl_(2)^(-) and Cu(CN)_(2)^(-)`
C. Copper (II) oxide is red powder
D. Hydrated `CuSO_(4)` is `[Cu(H_(2)O)_(4)]SO_(4).H_(2)O`

Answer

To determine which statement regarding copper salts is not true, we will analyze each statement one by one.

1. **Statement 1**: Copper(I) disproportionates into copper(0) and copper(II) in aqueous solution.
- Disproportionation is a reaction where a single substance is both oxidized and reduced. In this case, copper(I) (Cu^+) can be oxidized to copper(II) (Cu^2+) and reduced to elemental copper (Cu^0). This reaction is indeed possible:
\[ 2Cu^+ \rightarrow Cu^0 + Cu^{2+} \]
- This statement is **true**.

2. **Statement 2**: Copper can be stabilized by formation of insoluble complex compounds such as CuCl2^- and CuCN2^-.
- Copper(I) can form stable complexes with various ligands. For example, Cu^+ can react with chloride ions to form insoluble complexes like CuCl2^-. Similarly, it can form complexes with cyanide ions. Therefore, this statement is also **true**.

3. **Statement 3**: Copper(II) oxide is a red powder.
- Copper(I) oxide (Cu2O) is known to be a red powder, while copper(II) oxide (CuO) is actually a black solid. Thus, this statement is **not true**.

4. **Statement 4**: Hydrated copper sulfate is CuH2O4SO4·H2O.
- The correct formula for hydrated copper sulfate is CuSO4·5H2O. The statement provided is incorrect in its representation, but it can be interpreted that hydrated copper sulfate does exist. However, the formula given is not accurate. Therefore, this statement is also **true** in the context that it refers to hydrated copper sulfate, but the formula is incorrect.

Based on the analysis, the statement that is **not true** is:

**Copper(II) oxide is a red powder.**