Final answer:
The identity of the unknown metal in the hydrochloric acid solution is zinc (Zn).
Step-by-step explanation:
Based on the experimental data provided, the identity of the unknown metal (X) in the hydrochloric acid solution can be determined. When solid metal zinc reacts with hydrochloric acid, it forms a solution of colorless Zn²+ ions, Cl ions, and hydrogen gas. The balanced chemical equation for this reaction is:
Zn (s) + 2 HCl (aq) → ZnCl₂ (aq) + H₂ (g)
Therefore, the correct answer is C) Zinc (Zn).