Chapter 16, Problem 16.92QP

Interpretation Introduction

Interpretation:

The three common chromium oxides are $\text{CrO}$, ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{3}}$, and ${\text{CrO}}_{\text{3}}$. If ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{3}}$ is amphoteric, what can you say about the acid-base properties of $\text{CrO}$ and ${\text{CrO}}_{\text{3}}$ has to be explained.

Concept Information:

Oxides of metals and non-metals may be,

Acidic        -    exhibits acidic character

Basic        -    exhibits basic character

Amphoteric    -    exhibits both acidic and basic  character

Neutral        -    does not exhibit any of the acidic or basic character

Order of Basicity:

The basicity of metal oxides depends on the oxidation number of the metal ions.

The most basic oxides occur with metal ions having the lowest positive charges (or lowest oxidation numbers).

Metallic compounds in which the oxidation numbers of the metals are low are more ionic than those in which the oxidation numbers of the metals are high

Metal ions with high oxidation numbers are unstable.

Consequently, these metals tend to form covalent bonds (rather than ionic bonds) with oxygen.

To Explain: The acid-base properties of $\text{CrO}$ and ${\text{CrO}}_{\text{3}}$