5. As the pharmacist at a rural clinic in Ecuador, you have been asked to make 5
ID: 549044 • Letter: 5
Question
5. As the pharmacist at a rural clinic in Ecuador, you have been asked to make 550.0 mL of an eye wash solution (0.250 M H3B03) using deionized water and a stock boric acid solution (3.75 M H3BO3). Your technician offers to make the solution. She adds enough water to 50.0 mL of the stock solution to make a 250.0 ml of dilute boric acid a. What is the molarity of the solution made by your technician? Show your work. Box your final answer Did your technician make the solution you need? If not, explain (using words) how you could correct the concentration (not by starting over....) using some of the solution she prepared. Show all calculations. b.Explanation / Answer
a) 3.75 M means, in 1L solution, 3.75 moles of H3BO3 is there.
So in 50 mL (0.05 L) solution moles of H3BO3 present = 3.75 x 0.05 = 0.1875 moles.
Final volume = 250 mL (0.25 L),
Therefore concentration of new solution = moles/volume = 0.1875/0.25 = 0.75M.
b) No, I needed 0.25 M solution, where as the technician prepared 0.75 M solution.
We can take small volume from the solution the technician prepared and dilute it to required volume that is 550 mL.
We will use the formula C1V1 = C2V2
0.75M x V1 = 0.25M x 550 mL
Therefore V1 = (0.25 x 550)/0.75 = 183.3 mL
So in standard flask pippette out 183.3 mL of the solution prepared by technician and dilute it to make it to exact 550 mL by adding water in it.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.