Final answer:
To classify salts as acidic, basic, or neutral, one should look at the pH after salt dissolution. The property referred to is pH, determined by the acid-base properties of the salt's ions. Examples like KBr, NaHCO3, Na₂HPO4, and NH4F show how the constituents of the salt affect its pH.
Step-by-step explanation:
Classifying Salt Solutions by pH
To classify each salt as acidic, basic, or neutral, you need to consider the acid-base properties of the ions in the salt. The property referred to in this context is pH. Salts that contain the conjugate base of a weak acid (anions) generally form basic solutions upon dissolving in water, while salts with the conjugate acid of a weak base (cations) tend to be acidic. If both the anion and cation come from strong acids and bases, the resulting salt solution is typically neutral.
Let's look at the provided examples:
(d) NH4F - Acidic, because NH4+ is the conjugate acid of the weak base NH3 and F- is the conjugate base of HF, which is a weak acid but its conjugate base F- is not sufficiently basic to neutralize the effect of NH4+.
The pH of a salt solution, therefore, gives us an indication of whether it is acidic or basic.