What is the molarity of each kind of ion in a solution of magnesium chloride that contains 86.0 g of magnesium chloride dissolved in enough water to make 2.37 L of solution?

Question

M Mg2+
M Cl-

Answer 1

mols MgCl2 = grams/molar mass
M MgCl2 = mols MgCl2/L soln.

There is 1 mol Mg^2+ in 1 mol MgCl2; therefore, (Mg^2+) = (MgCl2)
There are 2 mols Cl^- in 1 mol MgCl2; therefore, (Cl^-) = 2 x (MgCl2)