Cathodic Protection Tester Practice Exam

What is the most active metal in freshwater conditions?

1. Copper

2. New steel

3. Zinc

4. Electrolytic aluminum

The correct answer is: New steel

In freshwater conditions, the most active metal referred to in this context is new steel, particularly when considering its potential to corrode. New steel typically has a higher reactivity than other metals like copper and aluminum when submerged in water due to the presence of iron, which is more susceptible to oxidation and corrosion processes. Freshwater environments can present various electrochemical reactions where metals will react with water or oxygen, leading to corrosion. New steel, being primarily composed of iron, tends to lose electrons more readily compared to metals like copper and aluminum, which are less active in terms of corrosion. While zinc has its uses in cathodic protection as an anode due to its ability to sacrifice itself to protect other metals, it does not surpass the inherent reactivity of new steel in this specific scenario. Thus, the nature of fresh water and its interaction with different metals establishes new steel as the most active metal when considering corrosion and reactivity.