20.3 The acid dissociation constant Ka

• In aqueous solutions, strong acids completely dissociate
• In aqueous solutions, weak acids partially dissociate
• The acid dissociation constant Ka is the equilibrium constant that measures the extent of acid dissociation
• Ka = ([H+][A-])/[HA]
• The larger the value of Ka, the greater the dissociation and the stronger the acid
• pKa = -log(Ka)
• Ka = 10^-pKa
• The stronger the acid, the larger the Ka value and the smaller the pKa value
• The weaker the acid, the smaller the Ka value and the larger the pKa value