During the analysis of an unknown acid HA, a 0.010 m solution of the sodium salt of the acid was found to have a pH of 10.35. Use Table 6C.1 to identify the acid.

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TABLE 6C.1 Acidity Constants at 25 °C* K₂ 3.0 X 10-1 2.0 X 10-1 1.7 X 10-1 1.5 X 10-2 1.0 × 10-2 7.6 X 10-3 1.4 x 10-3 8.4 X 10-4 4.3 X 10-4 3.5 x 10-4 Acid trichloroacetic acid, CC13COOH benzene sulfonic acid, C,H,SO3H iodic acid, HIO3 sulfurous acid, H₂SO3 chlorous acid, HClO₂ phosphoric acid, H3PO4 chloroacetic acid, CH₂CICOOH lactic acid, CH₂CH(OH)COOH nitrous acid, HNO₂ hydrofluoric acid, HF pK₂ 0.52 0.70 0.77 1.81 2.00 2.12 2.85 3.08 3.37 3.45 Acid formic acid, HCOOH benzoic acid, C,H,COOH acetic acid, CH₂COOH carbonic acid, H₂CO3 hypochlorous acid, HCIO hypobromous acid, HBrO boric acid, B(OH)3¹ hydrocyanic acid, HCN phenol, C,H,OH hypoio dous acid, HIO K₂ 1.8 X 10 4 6.5 x 10-5 1.8 x 10-5 4.3 X 10-7 3.0 X 10-8 2.0 × 10-9 7.2 X 10-10 4.9 X 10-10 1.3 X 10-10 2.3 × 10 11 pKa 3.75 4.19 4.75 6.37 7.53 8.69 9.14 9.31 9.89 10.64