Which of the following is a strong acid in aqueous solution?

• A. $H{F}_{\mathrm{}}$
• B. $C{H}_{3}COOH$ (acetic acid)
• C. $H_{2}C{O}_3$ (carbonic acid)
• D. $HCl$

Answer: (D)

Verified step by step guidance

1. Identify the acids given in the problem: HF (hydrofluoric acid), CH3COOH (acetic acid), H2CO3 (carbonic acid), and HCl (hydrochloric acid).
2. Recall the definition of a strong acid: a strong acid completely dissociates into its ions in aqueous solution, meaning it donates protons (H\textsuperscript{+}) fully.
3. Evaluate each acid's strength based on common knowledge: HF is a weak acid because it does not fully dissociate; acetic acid (CH3COOH) is a weak acid due to partial dissociation; carbonic acid (H2CO3) is also weak and partially dissociates.
4. Recognize that HCl is a strong acid because it completely dissociates in water, releasing H\textsuperscript{+} ions and Cl\textsuperscript{-} ions fully.
5. Conclude that among the options, HCl is the strong acid in aqueous solution.