Question

Which of the following is a strong acid?

• A. CH\(_3\)COOH
• B. HCl
• C. NH\(_4^+\)
• D. H\(_2\)CO\(_3\)

Hint:

Key Fact: Strong acids dissociate completely in water. Common examples include HCl, HNO\(_3\), and H\(_2\)SO\(_4\).

Answer 1

The Correct Option is B

To identify a strong acid, we must know that strong acids fully ionize in water, releasing a substantial quantity of hydrogen ions and thus exhibiting high acidity.

Let's examine the options:

• CH₃COOH (Acetic acid): This is a weak acid; it only partially dissociates in water, leaving some molecules intact.
• HCl (Hydrochloric acid): This is a strong acid that dissociates completely in water into H⁺ and Cl^- ions, resulting in strong acidity.
• NH₄⁺ (Ammonium ion): This is not typically considered an acid in isolation. It does not dissociate to yield hydrogen ions like strong acids.
• H₂CO₃ (Carbonic acid): This is a weak acid. Similar to acetic acid, it undergoes incomplete dissociation in water with a low ionization degree.

Consequently, HCl is the correct choice as it is the sole strong acid among the options, characterized by complete dissociation in aqueous solutions.