Electrochemical (partial reactions)

• Zn +2HCl = ZnCl2 + H2

  Zn + 2H+ = Zn2+ +H2
• Oxidation/ anodic reaction- produces e-

  Zn= Zn2+ + 2e-

  Reduction/cathodic reaction - consumes e

  2H+ + 2e- = H2
• stop one- stop corrosion

  usually reduce one ( slower one- cathodic)

  will reduce whole reaction
• corrosion rates in Fe:

  clean H2O<degassed HCl< HCl with O2<HCl with O2 + FeCL3

  last one is fastest because the cathodic reactions are slower than anode- is the limiting step
• Anodic and cathodic reactions are mutually dependent