Dilution calculation: use the formula M1V1=M2V2

How many milliliters of 12 M HCl would be needed to make 200 mL of a 1.0 M HCl solution?

I got 16.67 mL HCl for this part but there's a secondary question.

It says: How much water would be used to make this solution?

I have no clue what to do for that. Help, please and thank you.

1 answer

200*1 = x*12
x = 16.67 mL.

The problem states that you are making 200 mL; therefore, 16.67 comes from the 12 M stuff and 200-16.67 comes from added water. Technically, this isn't correct because the two solutions may not be additive but for dilution problems of dilute solutions these problems usually mean that we assume they are (exactly additive). The way we get around that, in real life, is we would add 16.67 mL of the 12 M stuff to a volumetric flask of exactly 200 mL, then add water to the mark to make the final solution exactly 200 mL. So how much water would we add. The answer is ABOUT 200-16.67. I think this problem wants that answer without the word about.:-)