Final answer:
Salt derives cations from bases because bases are proton acceptors according to the Brønsted-Lowry theory. Acids donate protons, and the proton transfer from acid to base during a reaction results in the formation of cations in salts from bases.
Step-by-step explanation:
The reason salt derives cations from a base rather than from an acid is that bases accept protons. According to the Brønsted-Lowry theory, a base is defined as a proton acceptor, while an acid is defined as a proton donor. This means that when salts are formed, typically through neutralization reactions, the cation in the salt comes from the base, as it is the recipient of the H+ ion from the acid, which upon losing the proton, forms the anion. Therefore, the correct answer to 'Why did salt derive cations from base? Why not from acid?' is D. Because acids donate protons. This aligns with the concept that in acid-base reactions, a proton transfer occurs from the acid (proton donor) to the base (proton acceptor).