Question

Non-metals react with oxygen to form _____ or ______.

• A. acidic oxides
• B. neutral oxides

Answer 1

Reaction of non-metals with oxygen:-

1. Oxygen and metals interact to generate their corresponding Metal oxides. The general equation predicts the course of this reaction as follows:
   Metal oxide$\to$Metal + Oxygen
2. These Metal oxides are created to react with water and then analysed using litmus paper to see how acidic or basic they are.
3. While blue litmus turns red in an acidic solution, blue litmus remains blue in a basic solution.
4. In contrast, non-metallic oxides react with water to generate acidic solutions, which liberate ${\mathrm{H}}^{+}$ ions in solution.
5. Metal hydroxides are alkaline in nature because they release ${\mathrm{OH}}^{-}$ ions in solution. Also, they react with weak acids to produce salt and water, metallic oxides are basic in nature.
6. Non-metallic oxides would therefore have an acidic character.
7. If a metal has more than one valence state, its oxide will be more acidic in the higher state it is in.
8. Oxygen and non-metals react to generate acidic or neutral oxides.
   ${\mathrm{O}}_2\left(\mathrm{g}\right)+\mathrm{C}\left(\mathrm{s}\right)\to {\mathrm{CO}}_2\left(\mathrm{g}\right)$
   $\mathrm{Carbon}+\mathrm{Oxygen}\to \mathrm{Carbon}\mathrm{dioxide}$
   $\mathrm{Non}-\mathrm{metal}+\mathrm{Air}\to \mathrm{Acidic}\mathrm{oxide}$

Acidic oxide:

When non-metals and oxygen combine, they produce acidic oxide compounds that are bound together by covalent bonds. These substances may also be referred to as acid anhydrides. Except for substances like ${\mathrm{B}}_2{\mathrm{O}}_3$ and ${\mathrm{SiO}}_2$, which have high melting points and form enormous molecules, acid anhydrides typically have a low melting and boiling point.

Examples: ${\mathrm{NO}}_2,{\mathrm{CO}}_2$

$$\begin{gathered} \underset{\mathrm{Sulphur}\mathrm{trioxide}}{{\mathrm{SO}}_3}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}}\to \underset{\mathrm{Sulphuric}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{SO}}_4} \\ \underset{\mathrm{Boron}\mathrm{oxide}}{{\mathrm{B}}_2{\mathrm{O}}_3}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}}\to \underset{\mathrm{Boric}\mathrm{acid}}{2{\mathrm{H}}_3{\mathrm{BO}}_3} \end{gathered}$$

Neutral Oxides:

Some substances react with oxygen to create oxides that neither have acidic nor basic properties. These substances are referred to as neutral oxygen compounds.

Examples: $\mathrm{CO},\mathrm{NO}$

Non-metals react with oxygen to form acidic oxides or neutral oxides.