Definition: A single replacement reaction is a chemical reaction in which one element replaces another element in a compound.
General Equation:
$$ A + BC → AC + B $$ * A is the element that replaces B
- B is the element that is replaced
- C is the common element in both compounds
Reactivity Series:
The reactivity of elements determines which element will replace another in a single replacement reaction. The reactivity series is a list of elements arranged in order of their decreasing reactivity. Elements at the top of the series are more reactive than those at the bottom.
Predicting Products:
To predict the products of a single replacement reaction, use the following rules:
- The more reactive element will replace the less reactive element in the compound.
- The element that is replaced will become the cation (positive ion) in the new compound.
- The element that replaces will become the anion (negative ion) in the new compound.
Examples:
- Zinc and copper sulfate:
$$ Zn + CuSO₄ → ZnSO₄ + Cu $$
- Iron and silver nitrate:
$$ Fe + 2AgNO₃ → Fe(NO₃)₂ + 2Ag $$
- Copper and hydrochloric acid:
$$ Cu + 2HCl → CuCl₂ + H₂ $$
Applications:
Single replacement reactions are used in a variety of applications, including:
- Electroplating: A coating of one metal on another
- Extraction of metals from ores: Removing impurities from metals
- Batteries: Generating electricity