When iron and copper are joined, which statement is true regarding their interaction?

The interaction between iron and copper can be understood through the principles of galvanic corrosion. When these two metals come into contact in an electrolyte, such as water, they form a galvanic couple. In this couple, copper, being less reactive and more noble than iron, acts as a cathode. Iron, on the other hand, acts as an anode, which is more susceptible to oxidation.

As a result, copper tends to protect iron from corrosion, making it less likely to corrode in the presence of moisture and electrolytes. This protective behavior is particularly significant when both metals are exposed to conditions that typically promote corrosion, such as in plumbing systems or various installation scenarios where moisture is present.

In contrast, if iron and copper were to interact differently, it would not provide the same degree of protection. For instance, if iron were to react with itself or with a more reactive metal, it would corrode more rapidly without any protective influence. Therefore, the assertion that copper protects iron from corrosion accurately reflects the electrochemical behavior of these two metals when they are in contact.