In which of the following is the entropy change positive?

Entropy is a measure of the randomness or disorder of a system. A positive change in entropy means that the disorder or randomness of the system has increased. -: H2O(I) → H2O(g) - When water vaporizes, it goes from a more ordered, liquid state to a more random, gaseous state. So, the entropy change will be positive. -: Cu2+(aq) + Fe(s) → Fe2+(aq) + Cu(s) - This is a redox reaction where copper ions are reduced to copper atoms while iron is oxidized to iron ions. Since a more ordered solid is converted into a less ordered solution, the entropy change will be negative. -: N2(g) + 3H2(g) → 2NH3(g) - Here, two gases combine to form a single gas, so the disorder of the system decreases, and the entropy change will be negative. -: 2HCl(s) → H2(g) + Cl2(g) - In this reaction, two solids combine to form two gases. As a result, the disorder of the system increases, and the entropy change will be positive. Therefore, the option in which the entropy change is positive is.