1. The problem statement, all variables and given/known data We throw clean Zn in a HCl solution and see that nothing happens. We add 2-3 drops CuSO4 and some kind of gas starts to release. Why dos this happen? Write the equation 2. Relevant equations Zn+HCl->ZnCl2+H2 3. The attempt at a solution I know that equation and also: Zn+CuSo4->ZnSo4+Cu But why doesn't H2 release in the first experiment? Maybe because it is too clean. COuld you also hep me with the general equation?