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QUESTION 2 A monoprotic weak acid. HA, Is titrated with strong base, Ba(OH)2 in

ID: 1034037 • Letter: Q

Question

QUESTION 2 A monoprotic weak acid. HA, Is titrated with strong base, Ba(OH)2 in aqueous solution. If so.00 mL of 0.1000 M HA is titrated with 0.1000 M Ba(OH)2 what is the pH of the titration solution at the equivalence point? Ka-2.5 x 10-5 for HA. Don't forget to take into account the added volume from the , note that the strong base has 2 OH in its addition of base titrant when determining the concentration of weak base, A, at the equivalence point. Also chemical formula. O 8.71 O 10.17 9.71 O 10.64 9.16

Explanation / Answer

Ba(OH)2   + 2 HA ---------------------> BaA2 + 2H2O

M1 V1 / n2 = M2 V2 / n2

0.1 x V1 / 1 = 0.1 x 50 / 2

V1 = 25 mL

volume of Ba(OH)2 = 25 mL

at equivalence point only salt left .

salt concentration = 50 x 0.1 / 25+50 = 0.067 M

pH = 7 + 1/2 [pKa + logC ]

pH   = 7 + 1/2 [4.60 + log 0.067]

pH = 8.71

answer : 8.71