Chemistry Regents Practice Test 2026 – The All-in-One Guide to Exam Success!

An acid-base reaction is characterized by the transfer of protons (H+ ions) from one species to another. In this type of reaction, acids are defined as proton donors while bases are regarded as proton acceptors. This fundamental concept is rooted in the Brønsted-Lowry theory of acids and bases, which emphasizes the behavior of protons in chemical reactions.

For instance, when hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), the H+ from HCl is transferred to the hydroxide ion (OH-) from NaOH, producing water (H2O) and sodium chloride (NaCl). This proton transfer is the hallmark of acid-base reactions and is essential to understanding many biochemical and industrial processes.

While reactions involving the formation of gas, production of precipitates, or oxidation of metals can occur in various chemical reactions, they do not specifically define acid-base reactions. Instead, these phenomena can be part of different types of reactions, such as gas evolution reactions, precipitation reactions, or redox reactions, which are unrelated to the transfer of protons characteristic of acid-base chemistry.