Acid is there a proton donor (H+)?

• A. A proton donor (H+)
• B. A proton acceptor
• C. A base
• D. A salt

Answer: (A)

In Bronsted-Lowry acid-base theory, an acid is defined as a substance that donates a proton (H+) to another species. That makes "proton donor" the best description of an acid. When an acid donates H+, the partner that accepts the proton is the base. For example, HCl donates a proton to water, producing hydronium (H3O+) and chloride. A base, on the other hand, accepts a proton to form a conjugate acid, like ammonia accepting a proton to become NH4+. A salt is simply an ionic compound formed from an acid and a base, not the acid itself. So the characteristic property of an acid is being a proton donor.