Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Help needed with Chemistry titration problem.?

19 2009:

100 mL of a soln that is 0.05M Sr^+2 and 0.05M Ra^+2 is titrated with 0.250 M SO4^-2. What is the pSO4 ^-2 after the addition of 48.6 mL of the base?

a. 2.65 b. 11.35 c. 10.39 d. 3.61

Explanation is necessary. Thank you.

1 Answer

Relevance
  • 1 decade ago
    Favorite Answer

    you have added 0.250 M* 48.6/1000 L= 0.01215 Moles of SO4 --

    sulphates become insoluble as you go down group 2 so all the Ra should be turned into RaSO4

    that is = 0.05 * 100/1000 = 0.005 Moles

    so that gets you down to 0.01215 - 0.005 moles of SO4-- left = 0.00715Moles

    The Sr will also for SrSO4 so use up more SO4--

    Amount of SrSO4 = 0.05 * 100/1000 = 0.005 moles

    so the amount of SO4-- left is 0.00715 - 0.005 = 0.00215Moles of SO4 --

    Now I am confused

    Are you asking for the percentage SO4--?

    ans which is the Base?? what Base

    I thought I had understood what you were after but it looks like I didn't

    Anyway hope this helps you understand what you need to do to finish it off

    S

    PS Let me know how you get on:)

Still have questions? Get your answers by asking now.