Which metal cannot displace hydrogen from dilute hydrochloric acid?

Step-by-step solution

1. Recall that a metal can displace hydrogen only if it is above hydrogen in the electrochemical series.
2. Check potentials: Mg, Zn, and Fe are more reactive than H${}^{+}$, so they give off H${}_2$, whereas Cu is below H${}^{+}$.
3. Therefore, copper cannot displace hydrogen from HCl.
4. The correct answer is the option that lists copper.

Concept tested: Displacement reactions with acids

Published 7 October 2026 · How this solution was prepared and checked