Question

YOU HAVE PREPARED 100.0ML OF A DILUTED FD&C RED DYE SOLUTION THAT HAS A CONCENTRATION OF 7.75*10^-5M. THE CONCENTRATION OF THE STOCK SOLUTION OF FD&C RED DYE WAS 2.97*10^-4M. WHAT vOLUME OF STOCK SOLUTION DID YOU USE TO CREATE YOUR DILUTED SOLUTION

Answer 1

Ans. Using      C1V1 (Stock solution) = C2V2 (diluted solution)

            Or, 2.97 x 10^-4 M x V1 = 7.75 x 10^-5 M X 100.0 mL

            Or, V2 = (7.75 x 10^-5 M X 100.0 mL) / (2.97 x 10^-4 M)

            Hence, V2 = 26.0943 mL

Therefore, required volume of the stock solution = 26.09 mL

Preparation of diluted dye solution: Take 26.09 mL of the stock dye solution in a clean 100-mL volumetric flask. Make the final volume upto the mark with distilled water. Mix well. The resultant solution is 100.0 mL of 7.75 x 10^-5 M dye.