Chapter 21, Problem 11STP

Interpretation Introduction

Interpretation: The method by which zinc blocks to a steel ship hull protects the steel from corrosion needs to be explained.

Concept Introduction: The activity series of a metal compares the reactivity of metals. Here, metals with high reactivity can replace metals with low reactivity from their solutions. Also, a metal with high reactivity can undergo oxidation faster than metals with low reactivity.

Explanation of Solution

The corrosion of steel is an oxidation reaction. Steel is an alloy of iron. The corrosion of steel can be represented as the oxidation of iron as follows:

  $\text{Fe}\left(s\right)\to {\text{Fe}}^{2+}\left(aq\right)+2e$

From the activity series, zinc is more reactive than iron thus, zinc can protect steel from corrosion as it gets oxidized.

The oxidation reaction of zinc is represented as follows:

  $\text{Zn}\left(s\right)\to {\text{Zn}}^{2+}\left(aq\right)+2e$

Therefore, due to the high reactivity of zinc, it can protect iron to gets oxidized or steel from corrosion.