Textbook 6N.23

[Ariel Lucas 1H]

Hi! I had a question about textbook problem 6N.23, I was wondering how you can tell what metals are used in cathodic protection, specifically why metals with lower standard reduction potentials can protect the cathode from corrosion. Thanks!

[Chem_14B_Student]

Metals with lower standard reduction potentials (more negative E° values) are preferred because they are more easily oxidized (lose electrons) than the metal to be protected. This means that when connected in a galvanic cell, the sacrificial metal will preferentially undergo oxidation (corrode) instead of the protected metal. For example, zinc and magnesium are commonly used as sacrificial anodes in cathodic protection systems for steel structures submerged in seawater. This is because zinc and magnesium have lower standard reduction potentials compared to steel, making them more susceptible to oxidation and corrosion in the presence of seawater. As a result, they sacrificed to protect the steel from corrosion.