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

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 

Answer 2

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.