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Titration, how does it work?

Discussion in 'MCAT Study Question Q&A' started by destroythemcat, Sep 6, 2014.

  1. destroythemcat

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    I'm a bit confused about titrations.

    When an acid is being titrated by a strong base.

    Acid before titration: HA-->H+ + A-

    When the strong base is added, lets say NaOH:

    1. Do the hydroxide ions reacts with H+ --> h2O and shift the equation to the right

    2. Or do the hydroxide ions react with HA causing the reaction to shift?

    hope someone can help me out
     
  2. kraskadva

    kraskadva ...
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    the OH- reacts with the H+ to form water.
    A- & B+ can either hang out in solution as spectator ions or come together to form a salt and precipitate out of solution.

    If you're starting with a strong acid, all the HA has dissociated to H+ & A- before the base is added and the equation doesn't shift back.
    If you're starting with a weak acid, as the OH- removes H+ from solution, the initial HA --> H+ & A- can shift further to the right (Le Chatlier's Principle) but will still eventually reach equilibrium and then be overwhelmed by the OH- as you continue to add base.
     
  3. OP
    OP
    destroythemcat

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    thank you!
     
    kraskadva likes this.

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