Suppose you want to prepare a solution of 2.50 L of 1.00 M HCl solution from concentrated 12.0 M HCl (aq). How many liters of concentrated acid is needed and how many liters of water is added?

Question

Already know the liters of concentrated acid needed. Trying to find the volume of water added.

Answer 1

You can use V1M1 = V2M2 to help solve this.

V1 = x L

M1 = 12.0 M

V2 = 2.50 L

M2 = 1.00 M

(x L)(12.0 M) = (2.50 L)(1.00 M)

x = 0.208 L = 208 mls of 12.0 M are needed to make 2.50 L of 1.00 M

Volume of H2O needed = 2.50 L - 0.208 L = 2.292 L = 2.29 L of water needed (assuming the volumes are additive)