400ml of 2.5M can be deluded to make how many of 2.0 HCI

The new volumen of the solution is 500 ml.

Explanation:

A dilution consists of the decrease of concentration of a substance in a solution (the higher the volume of the solvent, the lower the concentration).

We use the formula for dilutions:

C1 x V1 = C2 x V2

V2 = (C1xV1) / C2

V2 = (400 ml x 2,5 M) / 2,0M

V2 = 500 ml