Chapter 20, Problem 84A

Interpretation Introduction

Interpretation: Whether the coin made of magnesium or iron will tarnish faster is to be determined.

Concept introduction: Tarnishing of metals also called rusting of metals takes place as a result of oxidation and loss of electrons.

Answer to Problem 84A

  $Fe$ is more suitable to make coins than Mg.

Explanation of Solution

The oxidizing power of Mg is higher than that of $Fe$ . Mg losses its two-electron more readily than Fe. That is,

  $Mg\to M{g}^{2+}+2e^{-}$

Fe also undergoes oxidation,

  $Fe\to F{e}^{2+}+2e^{-}$

But the oxidation of Mg is faster. As Mg undergoes oxidation faster it is not suitable to make coins.