When an acid reacts with a metal such as magnesium, which of the following is typically produced?

• A. Hydrogen gas and a salt
• B. Ammonia and a complex ion
• C. Carbon dioxide and a base
• D. Oxygen gas and water

Answer: (A)

Verified step by step guidance

1. Understand the general reaction between an acid and a metal: when a metal like magnesium reacts with an acid, it typically undergoes a single displacement reaction where the metal displaces hydrogen from the acid.
2. Write the general form of the reaction: \(\text{Metal} + \text{Acid} \rightarrow \text{Salt} + \text{Hydrogen gas}\).
3. Recognize that magnesium (Mg) is a reactive metal that will react with acids such as hydrochloric acid (HCl) to produce magnesium chloride (a salt) and hydrogen gas (H\_2).
4. Recall that the other options (ammonia and complex ion, carbon dioxide and a base, oxygen gas and water) do not typically result from the reaction of a metal with an acid.
5. Conclude that the typical products of the reaction between magnesium and an acid are hydrogen gas and a salt.