A Metal which does not liberate $H_2$ from acid is?

Question

Accepted Answer

The correct option is (3):

Copper (Cu) is the metal that does not liberate hydrogen gas from acids. This behavior is explained by the reactivity series of metals. In the reactivity series, metals that are placed above hydrogen are more reactive than hydrogen and can displace hydrogen from acids, thus liberating hydrogen gas. Conversely, metals that are placed below hydrogen in the reactivity series are less reactive than hydrogen and cannot displace it from acids. Copper is one such metal that lies below hydrogen in the reactivity series, indicating its lower reactivity compared to hydrogen. Therefore, when copper reacts with dilute acids like hydrochloric acid or sulfuric acid, no hydrogen gas is produced.

The incorrect option is (1) Fe: Iron (Fe) is a metal that is more reactive than hydrogen and thus can displace hydrogen from acids to liberate hydrogen gas. For example, Fe + 2HCl → FeCl₂ + H₂.

The incorrect option is (2) Mn: Manganese (Mn) is also a reactive metal, positioned above hydrogen in the reactivity series. It readily reacts with acids to produce hydrogen gas.

The incorrect option is (4) Zn: Zinc (Zn) is a highly reactive metal, significantly above hydrogen in the reactivity series. It reacts vigorously with acids to liberate hydrogen gas, as seen in the reaction Zn + 2HCl → ZnCl₂ + H₂.