Acid Ionization Constants at 25°C

Name of Acid	Ionization Equation	Ka
Sulfuric acid	H2SO4 ⇌ H+ + HSO4− HSO4− ⇌ H+ + SO42−	very large 1.3 × 10−2
Oxalic acid	H2C2O4 ⇌ H+ + HC2O4− HC2O4− ⇌ H+ + C2O42−	6.5 × 10−2 6.1 × 10−5
Phosphoric acid	H3PO4 ⇌ H+ + H2PO4− H2PO4− ⇌ H+ + HPO42− HPO42− ⇌ H+ + PO43−	7.5 × 10−3 6.2 × 10−8 4.8 × 10−13
Hydrofluoric acid	HF ⇌ H+ + F−	7.1 × 10−4
Nitrous acid	HNO2 ⇌ H+ + NO2−	4.5 × 10−4
Benzoic acid	C6H5COOH ⇌ H+ + C6H5COO−	6.5 × 10−5
Acetic acid	CH3COOH ⇌ H+ + CH3COO−	1.8 × 10−5
Carbonic acid	H2CO3 ⇌ H+ + HCO3− HCO3− ⇌ H+ + CO32−	4.2 × 10−7 4.8 × 10−11
Hydrocyanic acid	HCN ⇌ H+ + CN−	4.9 × 10−10

Base Ionization Constants at 25°C

Name of Base	Ionization Equation	Kb
Methylamine	CH3NH2 + H2O ⇌ CH3NH3+ + OH−	5.6 × 10−4
Ammonia	NH3 + H2O ⇌ NH4+ + OH−	1.8 × 10−5
Pyridine	C5H5N + H2O ⇌ C5H5NH+ + OH−	1.7 × 10−9
Acetate ion	CH3COO− + H2O ⇌ CH3COOH + OH−	5.6 × 10−10
Fluoride ion	F− + H2O ⇌ HF + OH−	1.4 × 10−11
Urea	H2NCONH2 + H2O ⇌ H2CONH3+ + OH−	1.5 × 10−14

Calculate the change in pH when 8.00 ml. of 0.100 M HCI(aq) is added to 100.0 ml. of a buffer solution that is 0.100 M in NH, (aq) and 0.100 M in NH, CI(aq). Consult the table of ionization constants as needed. ApH Calculate the change in pH when 8.00 ml of 0.100 M NAOH is added to the original buffer solution. ApH =