* Activity Series: Copper (Cu) is less reactive than hydrogen (H). This means that copper cannot displace hydrogen from its compounds. The activity series is a ranking of metals based on their reactivity.

* Reaction with H₂SO₄: Copper will react with *concentrated* sulfuric acid (H₂SO₄) but not to replace hydrogen. Instead, it undergoes a redox reaction, where copper is oxidized to Cu²⁺ ions, and sulfuric acid is reduced to sulfur dioxide (SO₂). This reaction requires heat and produces a characteristic blue solution containing copper sulfate (CuSO₄).

In summary: Copper is not reactive enough to replace hydrogen from sulfuric acid. The reaction that occurs involves a redox process, not a simple displacement reaction.