Im stuck on this mastering chemistry problem and it seems that others are as wel
ID: 720581 • Letter: I
Question
Im stuck on this mastering chemistry problem and it seems that others are as well. SOme people believe that charges need to be included in the answers? Anyway:Decide whether or not each metal dissolves in 1 M HCl. For those metals that do dissolve, write a balanced redox reaction showing what happens when the metal dissolves.
1) Zn
2) Co
Au was part of the problem as well but I already lean red that it doesn't react. ANy help would be greatly appreciated!
Explanation / Answer
(A)Zinc dissolves in HCl. Yes charges should be included in the answer. It gives us a clearer picture about which species undergoes reduction or oxidation. Zn + 2HCl -> Zn2+ + H2 +2Cl- Zinc being an active metal & above H in the electochemical series displaces H Here, Zn is oxidised to Zn2+ (loses 2 electrons) H+ is reduced to H2 (gains 2 electrons) (B) The reaction with Cobalt is a bit complex. It actually forms a complex! (a coordination compound) Cobalt (II) chloride exists as the pink hydrated complex: [Co(H2O)6]2+ under room temp conditions. When conc. HCl is added it shifts the equilibrium so that the blue [CoCl4]2- ion is formed. [Co(H2O)6]2+ + 4Cl- --> [CoCl4]2- + 6H2O This is not the typical run of the mill redox reaction. However Cobalt does in this case, dissolve in Hcl. Hope this helps