3
$\begingroup$

In an experiment for standardisation of NaOH with titration, the lab manual instructed students to rinse conical flasks that were supposed to store 1mL aliquots of hydrochloric acid with distilled water.

Won't the excess water dilute the aliquot? Why not rinse with the HCl solution instead?

Thanks in advance.

Improve this question
$\endgroup$
3
  • 5
    $\begingroup$ The dilution with excess water won't affect the totat amount of HCl in the solution, which is what you will be titrating. You still know how much HCl you have from your quantitative addition of the 1 mL aliquiot. If you rinsed with HCl, you would have no idea how much HCl you really had and therefore you couldn't calculate the concentration of your NaOH. $\endgroup$
    – airhuff
    Mar 16, 2017 at 7:38
  • $\begingroup$ Thanks airhuff, I think I get it now. If I used HCl for rinsing, there will be more HCl in the flask than what I put in (1mL) and will therefore impact results. Thanks alot for the help. $\endgroup$
    – Bryan
    Mar 16, 2017 at 7:50
  • $\begingroup$ Technically, if you're doing very sensitive work, you would rinse with whatever you're about to use. This is assuming you can't just grab a new flask that doesn't have anything in it. $\endgroup$
    – Zhe
    Mar 16, 2017 at 13:47

1 Answer 1

Reset to default
3
$\begingroup$

The dilution with excess water won't affect the total amount of $\ce{HCl}$ in the solution, which is what you will be titrating. You still know how much $\ce{HCl}$ you have from your quantitative addition of the $\pu{1 mL}$ aliquiot. If you rinsed with $\ce{HCl}$, you would have no idea how much $\ce{HCl}$ you really had and therefore you couldn't calculate the concentration of your $\ce{NaOH}$.

Improve this answer
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.