Question

Could sodium be used as a sacrificial anode to protect the

iron hull of a ship?

Short answer

Theoretically, sodium can be used as a sacrificial anode to protect the iron hull of a ship. But, practically, it is not possible.

Step-by-step solution

Sacrificial anodes

Sacrificial anodes are also known as galvanic anodes. Some metals or alloys are attached to the hull, which has an anodic character. Such metals or alloys are known as sacrificial anodes. They can supply current to protect the cathode. It is named sacrificial because it is sacrificed to corrosion

Step 2: Replacement of sodium as a sacrificial anode

Generally, sacrificial anodes are selected based on the reactivity series. The metals on the top of the reactivity series are chosen for cathode protection, i.e., the sacrificial anode must lie above the parent metal in the reactivity series.

According to the reactivity series, sodium, potassium, calcium, magnesium, aluminum and zinc lie above iron. So sodium can be used as a sacrificial anode. But, when sodium is used as a sacrificial anode, it reacts with water rapidly and explosively. So, it becomes useless.