Question

A laboratory experiment requires 2.25 L of a 1.0 M solution of phosphoric acid (H3PO4), but the only available H3PO4 is a 9.0 M stock solution. How could you prepare the solution needed for the lab experiment? Show all the work used to find your answer.

Answer 1

We know that, M1V1 = M2V2
(Initial) (Final)

Given: M1 = 9.0 M
M2 = 1.0 M
V2 = 2.25 L

Therefore we have, 9.0 x V1 = 1.0 x 2.25
V1 = 0.25 L

Thus, 0.25 L of stock solution (9.0 M), when diluted till 2.25 L, the resultant solution will have concentration 1.0 M.

Answer 2

The solution needed is prepared as below

by use of the M1V1 =M2 V2 formula where
M1 = 2.25 L
v2 = 1.0M
M2 = 9.0 M
V2 =? l

make V2 the subject of the formula V2 =M1V1/M2

= 2.25 L x 1.0M/9.0 M = 0. 25 L

therefore the solution need 0.25 L of 9.0M H3PO4 and dilute it a final volume of 2.25 l