Question
A buffer solution is prepared by mixing 67.2 mL of 0.301 M carbonic acid with 57.7 mL of 0.0204 M sodium hydrogen carbonate.
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.
Table 10.2: pKa and pKb values at 25 C for some common weak acids and their conjugate bases Acid formula pKa Conjugate base Acid name Conjugate base name pKl CCOOH CCOO trifluoroacetic acid 0.20 trifluoroacetate ion 3.80 CI CCOOH 0.66 Cl3CCOO trichloroacetic acid trichloroacetate ion 3.34 HOOCCOOH 1.23 HOOCCOO oxalic acid hydrogen oxalate ion 12.77 dichloroacetic acid ClaHCCOOH 1.30 CI H CCOO dichloroacetate ion 12.70 sulfurous acid H2SO3 (HOSOOHj HSO. 1.77 hydrogen sulfite ion 12.23 hydrogen sulfate ion HSO, 1.92 SO sulfate ion 12.08 chlorous acid HCIO. 1.95 CIO. chlorite ion H PO. H PO phosphoric acid 2.12 hydrogen phosphate ion 11.88 chloroacetic acid CIH CCOOH 2.87 CIH CCOO chloroacetate ion 1.13 bromoacetic acid BrH CCOOH BrH CCOO bromoacetate ion 2.90 1.10 actic acid HE OCOOH 3.08 C2H5 ocoo lactate ion 0.92 2 H50 (COOH) 3.13 C3H50 (COOH) COOT dihydrogen citrate ion 0.87 citric acid 3 fluoride ion CaHTO COOH acetylsalicylate ion formate ion 5 7 4 COOH C5H7O4 COO ascorbic acid 4.10 ascorbate ion 9.90 hydrogen oxalate ion HOOCCOO OOCCOO 4.19 oxalate ion 9.81 4.20 C6Hscoo benzoic acid C6H5 COOH benzoate ion 9.80 C6H5NH 4.63 C6H5NH phenyl phenyl 9.37 ammonium ion amine (an ne
Explanation / Answer
It needs data like playing value of H2CO3
Its an example for Acidic Buffer and The formula for pH = pKa+log[initial concentration of salt x volume of salt]/initial concentration of salt x initial volume of acid]
we are adding acid to acidic buffer and it reaction reacts with salt and forms acid hence acid concentration (H+) increases and pH decreases slightly.
