Is this reaction a double displacement reaction? ${\mathrm{CH}}_3\mathrm{COOH}\left(\mathrm{aq}\right)+{\mathrm{NaHCO}}_3\left(\mathrm{s}\right)\to {\mathrm{CH}}_3\mathrm{COONa}\left(\mathrm{aq}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Double displacement reaction:

• When two compounds react, positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products is known as a double displacement reaction.
• A double replacement reaction is represented by the general equation, $\mathrm{AB}+\mathrm{CD}\to \mathrm{AD}+\mathrm{CB}$

Decomposition reaction:

• A reaction in which one reactant breaks down into two or more products is known as a decomposition reaction.
• This can be represented by the general equation is $\mathrm{AB}\to \mathrm{A}+\mathrm{B}$.

The reaction between Acetic acid$\left({\mathrm{CH}}_3\mathrm{COOH}\right)$ and Sodium bicarbonate $\left({\mathrm{NaHCO}}_3\right)$:

• Acetic acid$\left({\mathrm{CH}}_3\mathrm{COOH}\right)$ reacts with Sodium bicarbonate $\left({\mathrm{NaHCO}}_3\right)$ to form Sodium acetate $\left({\mathrm{CH}}_3\mathrm{COONa}\right)$ and Carbonic acid $\left({\mathrm{H}}_2{\mathrm{CO}}_3\right)$

$\underset{\mathrm{Acetic}\mathrm{acid}}{{\mathrm{CH}}_3\mathrm{COOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{bicarbonate}}{{\mathrm{NaHCO}}_3\left(\mathrm{s}\right)}\to \underset{\mathrm{Sodium}\mathrm{acetate}}{{\mathrm{CH}}_3\mathrm{COONa}}+\underset{\mathrm{Carbonic}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{CO}}_3\left(\mathrm{aq}\right)}$.

• This is a double displacement reaction because the $\mathrm{Na}$ is displaced with the $\mathrm{H}$ of ${\mathrm{CH}}_3\mathrm{COOH}$.
• The carbonic acid formed decomposes into ${\mathrm{CO}}_2$ and water

$\underset{\mathrm{Carbonic}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{CO}}_3\left(\mathrm{aq}\right)}\to \underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$.

• When two equations add together, the ${\mathrm{H}}_2{\mathrm{CO}}_3$ cancels out, that is

$\underset{\mathrm{Acetic}\mathrm{acid}}{{\mathrm{CH}}_3\mathrm{COOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{bicarbonate}}{{\mathrm{NaHCO}}_3\left(\mathrm{s}\right)}\to \underset{\mathrm{Sodium}\mathrm{acetate}}{{\mathrm{CH}}_3\mathrm{COONa}\left(\mathrm{aq}\right)}+\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

Therefore, the given reaction is a double displacement reaction.