Zn(s)+2hcl(aq)= zncl2(aq)+h2(g)
0.306 moles of hcl are required to consume all of the zn in the reaction mixture..
what is the volume of the solution that will deliver the required amount of the concentration is 2.5 m in hcl? what volume is required to prepare this solution from a concentrated (18m)?

There are a number of ways to express concentration of a solution. This includes molarity. Molarity is expressed as the number of moles of solute per volume of the solution. We calculate as follows:

2.5 M HCl = 2.5 mol HCl / L soln

0.306 mol HCl / 2.5 mol HCl/L son = 0.1224 L soln needed

M1V1 = M2V2
18 M(V1) = 2.5 M(0.1224 L)
V1 = 0.017 L of the 18 M solution