Maleic acid, HOCOCH-CHCOOH, is a weak acid with two protons (i.e. H2A. ka the fo

Question

Maleic acid, HOCOCH-CHCOOH, is a weak acid with two protons (i.e. H2A. ka the following questions. 1.23 x 10-2, ko2 4.66 x 10-7). Using a strong base solution (0.05000 M NaOH) to titrate 33.00 m of 0.01000 M H2A, answer Calculate the volume of the base solution used to reach the equivalent point for the second proton of maleic acid in milliliters. Subrnit Answer Incor Tries 7/25 Previous Tries Calculate the pH value at the second equivalent point. Read the textbook (Quantitative Chemical Analysis, 8th Ed. Daniel Harris, page 209-210)) Submit Answer Incor Tries 1/25 Previous Tries

Explanation / Answer

a) H2A(aq) + 2NaOH(aq) ---> Na2A(aq) + 2H2O(l)

1 mol H2A = 2 mol NaOH

M1V1/n1 = M2V2/n2

(0.01*33.00/1) = (0.05*V2/2)

v2 = volume of NaOH(base) required = 13.2 ml

b) after titration, total acid converts into salt.

concentration of salt = 0.01*33/(33+13.2) = 0.00714 M

pH = 7+1/2(pka2+logc)

pka2 = -logka2

      = -log(4.66*10^-7)

      = 6.33

     = 7+1/2(6.33+log0.00714)

     = 9.09

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