How to prepare 250ml of 2.5m solution of HCL

Answer 1

If you REALLY want 2.5 m (m means molal, not molar), then dissolve 2.5/4 mol HCl in 0.250 L H2O. The resulting solution may or may not be 250 mL.

If you want 2.5 M (molar) and I suspect you do, then dissolve 2.5/4 mol HCl in some water and make to a total volume of 250 mL.