Which general equation describes the reaction of a metal with an acid?

Which general equation describes the reaction of a metal with an acid?

• A. Salt + hydrogen
• B. Hydrogen gas + metal
• C. Metal oxide + water
• D. Salt + water

Answer: (A)

When a metal reacts with an acid, the products are a salt and hydrogen gas. The general equation is metal + acid → salt + hydrogen. The option that lists the products as “Salt + hydrogen” matches what is formed in this reaction, since the acid provides hydrogen that is released as H2 while the metal forms a salt with the remaining anion of the acid (for example, Mg + 2HCl → MgCl2 + H2). The other options describe different processes: hydrogen gas with the metal would imply an unusual reverse scenario, metal oxide + water is a reaction of metal with water or oxygen, and salt + water comes from neutralization with a base, not a metal reacting with an acid.

When a metal reacts with an acid, the products are a salt and hydrogen gas. The general equation is metal + acid → salt + hydrogen. The option that lists the products as “Salt + hydrogen” matches what is formed in this reaction, since the acid provides hydrogen that is released as H2 while the metal forms a salt with the remaining anion of the acid (for example, Mg + 2HCl → MgCl2 + H2). The other options describe different processes: hydrogen gas with the metal would imply an unusual reverse scenario, metal oxide + water is a reaction of metal with water or oxygen, and salt + water comes from neutralization with a base, not a metal reacting with an acid.