Question

What is the difference between a decomposition reaction and a replacement reaction?

Answer 1

A decomposition reaction is one where a compound is broken down into its constituent chemical species:

www.chemistryland.com
For example:

`2NaCl -> 2Na^+ + Cl_2^-`

The `NaCl` was broken down into the constituents `Na^+` and `Cl_2^-`

--(side note: the `Cl` is diatomic that explains the `2`)

There are two types of replacement reactions, observe the differences:

single replacement reactions chemistry,com
Single Replacement: `AB + C -> AC + B`

double replacement reaction from chemistrycom

Double Replacement: `AB + CD -> AD + CB`

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