In a schools laboratory, students require 50.0 mL of 2.50 M H2SO4 for an experiment, but the only available stock solution of the acid has a concentration of 18.0 M. what volume of the stock solution would they use to make the required solution

Work out the number of moles needed.

concentration = 2.5 mol/dm3 and volume = 0.05 dm3

volume * concentration = moles

now, using the concentration 18 mol/dm3 and moles calculated earlier, work out the volume needed.

rearrange the formula to make moles/concentration = volume

and get your answer.