# What is the difference between a double replacement and an acid-base reaction?

Aug 29, 2017

Although similar, neutralisation reactions do not displace the $H$ and $O H$ atoms, but rather react together to form water. This is not evident in double displacement reactions.

#### Explanation:

Generally speaking, a double displacement reaction has a formula of $A B + C D \to A D + C B$. This normally occurs between two ionic compounds but is not restricted to it *needs confirmation.

An acid-base reaction is a neutralisation reaction in which the hydrogen and oxygen atoms within the acid and base yields water, while the other reactants form a salt.

This means that they don't displace each other, but rather forms a new compound.

Examples:

Double displacement

BaCl_"​2" ​​ (aq)+Na_"2"SO_"4" ​​ (aq)→BaSO_"4" ​(s)+2NaCl (aq)

You see that the $A B + C D \to A D + C B$ formula applies, where:
=> $A$ refers to $B a$.
=> $B$ refers to $C l$.
=> $C$ refers to $N a$.
=> $D$ refers to $S {O}_{\text{4}}$.

Neutralisation

${H}_{\text{2"SO_"4" + 2KOH -> K_"2"SO_"4" + 2H_"2}} O$

As you can see, the $H$ and $O H$ atoms form water, while the other reactants ($K$ and $S {O}_{\text{4}}$) form ${K}_{\text{2"SO_"4}}$.

Hope this helps :)