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Strong Base - Weak Acid ?

  1. Jan 4, 2005 #1

    Im trying to determine the initial molarity of an unknown acid, sooo im trying to titrate it with standardized sodium hydroxide solution (0.1M). But im having a load of problems figuring out what the heck im supposed to do since i am told the acid is a weak acid.

    If im titrating a weak acid using a strong base the equivalence point is at a pH level greater than 7 correct?

    But im not supplied with information regarding anything about the acid except that it is weak, and nothing about the pH at the equivalence point!!

    How would i go about doing this titration ??? Does buffers have anything to do with this (since according to my textbook, the acid-base buffer should form around the halfway point to the equivalence point).
  2. jcsd
  3. Jan 4, 2005 #2


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    Buffers do not have anything to do with it since strong acid/bases have no relation to buffers.

    here are some hints:

    Titrate to completion, at the equivalence point, that is when the acid and base have reacted in stoichiometric equivalence, the final pH will be determined by the salt formed in the reaction.

    from this pH you should be able to determine the pKa of the weak acid.
  4. Mar 31, 2009 #3
    Why is it better to use a weak base(such as calcium carbonate) to neutralise strong acid (such as hcl) rather than strong base?

    Thank you so much
  5. Mar 31, 2009 #4


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    Please don't hijack threads.

    And remember we want you to try first. You do have some ideas, don't you?
    Last edited: Mar 31, 2009
  6. Mar 31, 2009 #5
    no i dont have a correct answer but i think it is because weaker acid is less likely to make the solution alkali therefore acidic salt is produced
  7. Mar 31, 2009 #6


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    If you start with a neutral solution, and you add calcium carbonate, what will be the final pH?
  8. Mar 31, 2009 #7


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    The use of Calcium Carbonate might be a choice to employ the insolubility of calcium carbonate after all of the acid is neutralized, but is this practical/useful?

    This "hijack" was also on another board, and I gave a response there.

    BETTER: Start a new topic and not continue this "Calcium Carbonate - Strong Acid" topic here.
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