87.13 Corrosion and protection of metals 2. Theoretical consideration Conjugation reaction Zn+2 HCI-> ZnC2+ H anode reaction Zn->Zn2++2e Cathode reaction: 2H++2e>H Why does Zn of 99.5 purity dissolve in dilute HCl in 1 min, while that of 99.999% purity does not dissolve even after 8 h?2. Theoretical consideration Zn + 2 HCl ⎯→ ZnCl2 + H2 Why does Zn of 99.5 % purity dissolve in dilute HCl in 1 min, while that of 99.999% purity does not dissolve even after 8 h? anode reaction: Zn ⎯→ Zn2+ + 2e− Cathode reaction: 2H+ + 2e−⎯→ H2 Conjugation reaction §7.13 Corrosion and protection of metals