In a clean 250-mL volumetric flask, 125 mL of a 6.0 M hydrochloric acid was added. This was then diluted with more water to reach the 250-mL mark. What is the molarity of the acid at this time?

Answer 1

use the equation CsVs=CdVd
Cs = Concentration of Stock (6.0M)
Vs = Volume of Stock (125mL)
Cd = Concentration of Diluted (??)
Vd = Volume of Diluted (250mL)

you are looking for the concentration or molarity of the diluted version of the hydrochloric acid because water was added to the 125mL of the acid.

so 6.0x125 = Cd x 250

no you isolate the Cd ..
6.0x125/250 = Cd

then you will get your answer, do you understand??