Answer:
2
Explanation:
well since the question has given you the concentration of the solution 0.2mol/L and the wanted amount (moles) of naoh(0.4mol) you are able put this into the formula n=cV; where n is the moles of naoh the solution, c is the concentraton of the solution and V is the volume of the solution in litres.
therefore the for the solution to have 0.4 moles of naoh you put it into the formula, giving you:
0.4 = 0.2V
V = 2
V = 2 litres
