What molarity should the stock solution be if you want to dilute 25.0mL to 2.00L and have the final concentration be 0.103M ?
A)0.206 M
B)8.24 M
C)4.12 M
D)0.243 M
E)none of the above

Question

Quizplus · Accepted Answer

First, use the dilution equation: 
M1V1 = M2V2 
where M1 is the initial concentration (unknown), V1 is the initial volume (25.0 mL = 0.025 L), M2 is the final concentration (0.103 M), and V2 is the final volume (2.00 L). 
Rearranging the equation to solve for M1: 
M1 = (M2V2)/V1 
M1 = (0.103 M)(2.00 L)/(0.025 L) 
M1 = 8.24 M 
Therefore, the stock solution should be 8.24 M in order to dilute 25.0 mL to 2.00 L and have the final concentration be 0.103 M.

What Molarity Should the Stock Solution Be If You Want