The solubility of MnSO4 in water at 20 degrees celcius is 70 g per 1000 mL of water. Is a 1.22 M solution of MnSO4 in water saturated, supersaturated, or unsaturated?
The molar mass of MnSO4 is (55 + 32 + 4×16) = 151.
At 20ᵒC, the solubility of MnSO4 in water is 70 g per 1000 mL
= 70/151 moles per 1000 mL
= 0.463576 M.
The given solution is 1.22 M, which is greater than the solubility (the maximum possible solute at a temperature that could be kept into solution, without precipitation).
Hence the 1.22 M nSO4 solution is supersaturated. Some amount of solid MnSO4 is expected to be thrown out of this solution in the form of precipitate to bring down the solute concentration a maximum of 0.463576 M, at 20ᵒC.