# Is Na + HCl = H2 + NaCl a double displacement reaction??

Feb 21, 2017

No, it is a single displacement reaction.

#### Explanation:

No.

Double displacement reactions have the general formula of $A B + C D \to A D + C B$. Where each letter is either an element or polyatomic ion.

Single displacement reactions have the general formula of $X + Y Z \to Y + X Z$ - in which the cation displaces another cation/hydrogen, OR $X + Y Z \to Z + Y Z$ - in which an anion displaces another anion. Each letter is either an element or polyatomic ion.

Single displacement reactions are typically based off of the activity series:

A cation $\left(A\right)$ can only displace another cation $\left(B\right)$ if $\left(A\right)$ is higher than $\left(B\right)$ on the series. This is all based off of ionic bonds, in which electrons are transferred.

Here, we see sodium is much higher than hydrogen, therefore we can conclude a reaction occurs. In addition, only 3 elements (no polyatomic ions so I won't talk about it) are presented, indicating a single displacement reaction. A double displacement reaction typically has 4 elements (again, not including polyatomic ions).

Hope this helps :)