Even though most metal sulfides are sparingly soluble in water, their solubilities differ by several orders of magnitude. Thisdifference is sometimes used to separate the metals by controlling the pH. Use the following data to find the pH at which you can separate 0.10 M Cu²⁺ and 0.10 M Ni²⁺: Saturated H₂S = 0.10 MKₐ₁ of H₂S=9x10⁻⁸ & Kₐ₂ of H₂S=1x10⁻⁷Ksp of NiS = 1.1x10⁻¹⁸ & Ksp of CuS = 8x10⁻³⁴