Problem- Calculate the molarity of a solution made by adding 39.9 mL of concentrated perchloric acid (70.5 % by mass, density 1.67 g/mL) to some water in a volumetric flask, then adding water to the mark to make exactly 2000 mL of solution. (It is important to add concentrated acid or base to water, rather than the other way, to minimize splashing and maximize safety.)
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