A solution contains 9.25x103 M copper(II) nitrate and 1.40x102 M manganese(II) acetate. Solid potassium carbonate is added slowly to this mixture. A. What is the formula of the substance that precipitates first?
B. What is the concentration of carbonate ion when this precipitation first begins?

Explanation:

Concentration of Cu⁺² = 9.25 x 10³ M

Concentration of Mn⁺² = 1.4 x 10² M

solubility product of copper carbonate = 7.08 x 10⁻⁹

solubility product of manganese  carbonate = 2.24 x 10⁻¹¹

solubility product of later is less so carbonate of manganese will come out first .

B )

[ Mn⁺² ] [ CO₃⁻² ] = 2.24 x 10⁻¹¹

1.4 x 10²  [ CO₃⁻² ] = 2.24 x 10⁻¹¹

[ CO₃⁻² ] = 1.6 x 10⁻¹³ .

the concentration of carbonate ion when this precipitation first begins

= 1.6 x 10⁻¹³ M .