Standard solutions of calcium ion used to test for water hardness are prepared by dissolving pure calcium?

standard solutions of calcium ion used to test for water hardness are prepared by dissolving pure calcium carbonate, CaCO3, in dilute hydrochloric acid. A 1.745-g sample of CaCO3 is placed in a 250.0-ml volumetric flask and dissolved in HC1. Then the solution is diluted to the calibration mark of the volumetric flask. Calculate the resulting molarity of calcium ion.