136. Solving a chemistry problem

To determine Ca2 ions in the presence of magnesium, an excess of NaOH was added to 20.00 cm3 of water to determine Mg2 ions in the form of hydroxide, and to 20.00 cm3 of 0.05 M complexone III. For titration of the excess of the latter, 12.15 cm3 of a 0.0485 M solution of calcium chloride with an indicator - murexide was used. Calculate the content in the form of Ca2 ions in mol/dm3 in g/dm3