Metal vs. Nonmetal Oxides

Last updated
Save as PDF

Page ID: 3013

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

Chemical Concepts Demonstrated

Basicity of metal oxides
Acidity of nonmetal oxides

Demonstration

BaO is dissolved in water containing phenolphthalein.
The flask contains distilled water with bromothymol blue indicator already made blue by 0.1M NH₃. The test tube contains chunks of dry ice. The flask and the test tube are connected with glass tubing as shown in the picture.
Red phosphorus is ignited and immersed in a flask of O₂ gas. The P₄O₁₀ produced is dissolved in water that contains bromothylmol blue indicator already made blue by 0.1M NH₃.

Observations

The solution turns from colorless to pink.
As the CO₂ is given off, the indicator changes from blue to green and then to yellow,
The solution turns from blue to green to yellow.

Explanations (including important chemical equations)

Metal oxides that dissolve in water react with water to form basic solutions.

BaO (s) + H₂O(l) ---> Ba ²⁺(aq) + 2 OH^- (aq)

Nonmetal oxides react with water to from acidic solutions.

CO₂ (g) + H₂O(l) ---> H₂CO₃ (aq)

P₄O₁₀ (s) + 6 H₂O(l) ---> 4 H₃PO₄ (aq)

Contributors

Dr. George Bodner (Perdue University)