Florida Drinking Water Operator "B" Practice Test

Where do aluminum, zinc, and magnesium rank in the galvanic series?

1. Least active metals

2. Moderately active metals

3. Most active metals

4. Passive metals

The correct answer is: Most active metals

Aluminum, zinc, and magnesium are classified as the most active metals in the galvanic series. The galvanic series is a ranking of metals based on their electrochemical activity, where more active metals corrode faster when in contact with less active metals. Aluminum, zinc, and magnesium have a high tendency to lose electrons and undergo oxidation, which makes them very reactive in various environments, particularly in the presence of moisture and electrolytes. Their position in the series indicates that they will sacrifice themselves to protect less active metals, a principle often applied in galvanic protection systems, such as using zinc sacrificial anodes to protect iron or steel structures from corrosion. This substantial reactivity is crucial for applications that involve corrosion mitigation and the selection of materials in environments where galvanic corrosion might occur.