How many ml of a 0.155 m kcl solution contain 2.55 g kcl?

To determine te volume of the solution given the amount of solute present, we simply divide the amount in moles with the concentration in molarity. First, we make sure the amount of solute is expressed in moles.

moles KCl = 2.55 g KCl / 74.55 g/mol = 0.0342 mol KCl

Volume of solution = 0.0342 mol / 0.155 mol / L = 0.221 L solution or 221 mL of the solution