A solution contains Cr3+ ion and Mg2+ ion. The addition of 1.00 L of 1.55M NaF solution is required to cause the complete precipitation of these ions as CrF3(s) and MgF2(s). The total mass of the precipitate is 49.9g .Find the mass of Cr3+ in the original solution.
1 answer
Mass of Cr3+ = (49.9 g) x (3 mol Cr3+/1 mol CrF3) x (1 mol Cr3+/1 mol Mg2+) x (24.3 g Cr3+/1 mol Cr3+) = 37.2 g Cr3+