Ammonia is a weak base, as indicated by the pK_a,_A and pK_a,_B values in Table 18.2. Determine the percentage of NH₃ dissociated at pH 7 and pH 1.5 when the apparent amount of NH₃ in aqueous solution is 0.15 m. Assume ideal solutions.

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Strong Acids Increasing Acid Strength Table 18.2 Reference Table for Relative Acid and Base Strengths at 25°C Based on pKa,water = -13.995. pKz 13.995-pka Species Perchloric acid Hydrogen chloride Sulfuric acid Nitric acid Hydronium ion Sulfurous acid Bisulfate Phosphoric acid Hydrofluoric acid Acetic acid Total dissolved CO₂ Hydrogen sulfide Dihydrogen phosphate Bisulfite ion Hypochlorous acid Hydrogen cyanide Boric acid Ammonium ion Bicarbonate Hydrogen phosphate Water Bisulfide Ammonia Hydroxide ion Acid HCIO4 HC1 H₂SO4 HNO3 H3O™ H₂SO3 HSO4 H3PO4 HF CH3COOH CO2(aq) + H₂CO3 H₂S H₂PO4 HSO3 НОСI HCN H₂BO4 |NH4 HCO3 HPO4 H₂O HS™ NH3 OH PKA Base ~-7 C104 ~-3 Cl -3 HSO4 -1 NO3 0 H₂O 1.857 HSO3 1.987 SO4 2.148 H₂PO4 3.17 F 4.756 CH3COO 6.351 HCO3 7.02 HS 7.198 HPO4 7.172 SO3 7.53 OCI 9.21 CN 9.237 B(OH)4 9.245 NH3 10.329 CO3 12.375 PO4³ 13.995 OH™ -14 S-2 ~23 NH2 -24 0² pKa,B 21 Increasing ~17 Base Strength ~17 ~15 13.995 12.138 12.008 11.847 10.825 9.239 7.644 6.98 6.797 6.823 6.47 4.79 4.758 4.750 3.666 1.620 0 ~0 -9 -10 N Strong Bases