Chemistry

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I took 25 mL of an unknown weak acid and added it to 10 mL of NaOH solution. I measured the pH and got 2.88 with concentration of NaOH @ .0098 and weak acid at 0.0102. What is pKa for the acid?

  • Chemistry -

    pH = pKa + log (base)/(acid)
    Set up an ICE chart and use the above equation.
    25.0 x 0.0102 = 0.255 mols
    10 x 0.0098 0.098 mols
    .........HA + OH^- ==> H2O + A^-
    I......0.255.....0........0.....0
    added.........0.098...........
    C....-0.098.-0.098......0.098
    E ....0.157...0..........0.098...

    Post your work if you get stuck.

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