Question

A buffer solution is prepared by mixing 15.5 mL of 0.0229 M pyridinium chloride with 73.8 mL of 0.888 M pyridine. A table of pKa values can be found here.


1. Calculate the pH (to two decimal places) of this solution.

Assume the 5% approximation is valid and that the volumes are additive.

pKa Conjugate base Acid formula Conjugate base name Acid name F3CCOOH 0.20 F3ccoo trifluoroacetic acid trifluoroacetate ion 13.80 Cl3CCOOH 13.34 0.66 Cl3CCOO trichloroacetic acid trichloroacetate ion HOOCCOOH 1.23 HOOCCOO oxalic acid hydrogen oxalate ion 12.77 Cl2HCCOOH 12.70 dichloroacetic acid 1.30 Cl2HCCOO dichloroacetate ion H2SO3 12.23 1.77 HSO3 sulfurous acid hydrogen sulfite ion 1.92SO42- HSO4 hydrogen sulfate ion sulfate ion 12.08 HCIO2 1.95 CI02 chlorous acid chlorite ion 2.12 H2PO.4 phosphoric acid H3PO dihydrogen phosphate ion 11.88 CIH2CCOOH 2.87 CIH2CCOO 11.13 chloroacetic acid chloroacetate ion BrH2CCOOH bromoacetic acid 2.90 BrH2CCOO bromoacetate ion 10.87 citric acid C3H50(COOH)s 3.13 C3Hs(COOH)2COO dihydrogen citrate ion hydrofluoric acid 3.20 F fluoride ion 10.80 3.37 NO2 HNO2 10.63 nitrous acid nitrite ion C8H702 COOH 10.52 acetylsalicylic acid 3.48 C8H702COO acetylsalicylate ion HCOOH 3.75 HCOO formic acid formate ion lactic acid C2H5OCOOH 3.86 C2HsOCOO lactate ion 10.14 9.90 4.10 C5H7O4CO ascorbate ion scorbic acid нооссоо 9.81 hydrogen oxalate ion oxalate ion 9.80 benzoic acid C6H5 COOH 4.20 C6H5 COO benzoate ion C6H5NH3+ 4.63 C6H5NH2 phenylamine (aniline phenylammonium ion 9.37

Tries 0/13

2. Calculate the pH (to two decimal places) of the buffer solution after the addition of 8.26 g of pyridine (C₅H₅N) to the buffer solution above.

Assume 5% approximation is valid and that the volume of solution does not change.

Tries 0/13

Answer 1

O 89 = 3,1) A d 79 Mw Mole。f.csM5yJ:05.5xD-b 22g入10 Tital + o.I oS 0 ,066 m.) 8 089