In the preparation of one liter of 2.5 M HCl solution, what is the volume of HCl

Question

concentrated (37% w / w, d = 1.19 g / ml) to be used?

Answer 1

Concentrated HCl is commonly 11.8M.

So you are diluting it 11.8/2.5 times, or 4.72 times. That means, you need one part conc HCl, and 3.72 parts water.
What is one part? 1000ml/4.72=2.118ml

so measure 2.2118ml*3.72=788.14 ml water, and add 2.118 ml of conc HCl slowly, stiring, wearing googles and gloves. Always do this under the vent hood, and always add acid to water.