Final answer:
For bases, a lower pH indicates a weaker base, as stronger bases have higher pH values due to their larger base-ionization constants (Kb), resulting in higher hydroxide ion concentrations in solution.
Step-by-step explanation:
For bases, the lower pH signifies a weaker base, not a stronger one.
Bases are substances that, in aqueous solution, react with water to produce hydroxide ions (OH−). The base-ionization constant (Kb) is used to measure the strength of a base; the larger the value of Kb, the stronger the base. The general reaction for a base in water can be represented as B(aq) + H2O(l) ⇒ HB+ (aq) + OH− (aq), where a stronger base results in a higher concentration of OH− in solution. Therefore, stronger bases have higher pH values, typically greater than 7, since pH is a measure of the hydrogen ion concentration and is inversely related to the hydroxide ion concentration. We can use hydrochloric acid (HCl) as an example for acids, as it completely dissociates, indicating high strength, whereas a strong base like sodium hydroxide (NaOH) will readily dissociate to give up OH−.