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    pH and Ka of lactic acid

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    3. Lactic acid, HC3H5O3, is a monoprotic acid that dissociates in aqueous solution, as represented by the equation(not given).

    Lactic acid is 1.66 % dissociated in 0.50M HC3H5O3. (aq) at 298K.

    A) Write the expression for the acid- dissociation constant , Ka , for lactic acid and calculate its value.

    B) Calculate the pH of 0.50M HC3H5O3.

    C) Calculate the pH of a solution formed by dissolving 0.045 mole of sodium lactate, NaC3H5O3 in 250ml of 0.50M HC3H5O3. Assume that volume change is negligible.

    D) A 100ml sample of 0.10 M HCL is added to 100ml of 0.50M lactic acid.
    Calculate the Molar concentration of the lactate ion C3H5O3- , in the resulting solution.

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    https://brainmass.com/chemistry/acids-and-bases/ph-ka-lactic-acid-176114

    Solution Preview

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    lactic acid eqbm question
    3. Lactic acid , HC3H5O3 , is a monoprotic acid that dissociates in aqueous
    solution , as represented by the equation ( not given )
    HC3H5O3 (aq)  H+ (aq) + C3H5O3- (aq)
    Lactic acid is 1.66 % dissociated in 0.50M HC3H5O3. (aq) at 298K.

    A) write the expression for the acid- dissociation constant , Ka , for lactic
    acid and calculate its value
    ...

    Solution Summary

    It shows how to determine the acid dissociate constant Ka of lactic acid. It further explains how to calculate the pH of the sodium lactate solution. The solution is detailed and well presented.

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