Final answer:
The concentration of Cu²⁺ will vary depending on the concentration of hydroxide ions; lower OH⁻ leads to lower Cu²⁺ concentration, while higher OH⁻ increases the concentration of Cu²⁺.
Step-by-step explanation:
The concentration of Cu²⁺ in a solution saturated with Cu₄(OH)₆(SO₄) depends on the concentration of hydroxide ions, OH⁻. With a low OH⁻ concentration, there is less tendency for the Cu₄(OH)₆(SO₄) to dissociate, and thus a lower concentration of Cu²⁺ ions. As the concentration of OH⁻ becomes moderate, more Cu₄(OH)₆(SO₄) will dissolve to maintain equilibrium, leading to a higher concentration of Cu²⁺. When the OH⁻ concentration is high, the solubility of Cu₄(OH)₆(SO₄) is further increased, and even more Cu²⁺ will enter the solution. If the OH⁻ concentration is variable, the Cu²⁺ concentration will also be variable, adjusting to maintain the solubility equilibrium. Therefore, without specific OH⁻ values, we cannot determine an exact concentration of Cu²⁺.