With which of the listed substances does iron react: CuCl2, TiO2, HCl, O2, H2O, MgSO4, CO2, Cl2, S?

Let’s implement the solution:
1. Fe + CuCl2 = Cu + FeCl2 – substitutions, ferric chloride (2) was obtained;
2. Fe + TiO2 – the reaction does not go.
3. Fe + HCl = FeCl2 + H2 – OBP, hydrogen, ferric chloride are released;
4. 3Fe + 4H2O = Fe3O4 + 4H2 – OBP, occurs in water vapor;
5. Fe + MgSO4 – the reaction is not progressing;
6. Fe + CO2 – practically impossible;
7. 2Fe + 3Cl2 = 2FeCl3 – compounds, ferric chloride (3) was formed;
8. Fe + S = FeS – iron sulfide obtained in the process of connection.
Iron is a metal of medium chemical activity; when interacting with acids, salts, it is necessary to take into account its position in the row of metal activity.