Reactions of acids with oxides

​​In a nutshell

Metal oxides react with acid to form a salt and water, similar to that of alkalis. Non-metals react with alkalis to form salt and water.

Equations

Metal oxides

Metal oxides are metal compounds which have an oxygen present.

Example

Iron oxide, Magnesium oxide

Metal oxides with acids

Metal oxides are alkaline and therefore they behave similar to alkaline solutions when reacting with acids. They form a salt and water.

$$acid\ + metal\ oxide\rightarrow\ salt\ +\ water$$

Example

​$$hydrochloric\ acid\ +\ magnesium\ oxide\ \rightarrow\ magnesium\ chloride\ +\ water\\\>\\ HCl\ +\ MgO\ \rightarrow\ MgCl\ +\ H_2O$$

Magnesium chloride is the salt produced when hydrochloric acid and magnesium oxide react together.​

Hydrochloric\ acid\ + Magnesium\ Oxide \rightarrow\ Magnesium\ chloride\ + water

Non-metal oxides

Non-metal elements such as silicon and sulphur can also react with oxygen to form oxides.

Example

​$$sulfur\ +\ oxygen \rightarrow\ sulfur\ dioxide$$

Two non-metals, sulfur and oxygen, react to form sulfur dioxide.​

Non-metal oxides behave as acids

Non-metal oxides exhibit acidic behaviour and therefore react with acids to form a salt and water.

Example

​$$alkali\ +\ non\>metal \rightarrow salt\ +\ water$$

$$sodium\ hydroxide\ +\ sulfur\ dioxide \rightarrow\ sodium\ sulfate\ +\ water$$

Sodium sulfate is the salt formed when sodium hydroxide and sulfur dioxide react together.​​