What type of chemical reaction is this?

So far we have learned about about single displacement, double displacement, gas evolving, neutralization, synthesis, disassociation, and combustion.


I was trying to solve the following chemical equation and I couldn't figure out under what category this reaction falls.


\*Aqueous lithium hydroxide reacts with gaseous carbon dioxide to produce aqueous lithium hydrogen carbonate.


$$\ce{LiOH(aq) + CO2(g) -> LiHCO3(aq)}$$ 


If this is a synthesis, how can the base combine with $\ce{CO2}$? 




There are many ways of describing this reaction, but the word that comes to mind is *addition*, because $\ce{OH^-}$ adds to $\ce{CO\_2}$.


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Lewis theory would suggest it to be an acid-base:
CO2 behaves as electron pair acceptor from OH-


[![enter image description here](https://i.stack.imgur.com/F1rDV.jpg)](https://i.stack.imgur.com/F1rDV.jpg)


However, it is not compulsory to classify a reaction into just one type:
The given reaction could also be called synthesis, as simpler molecules combine to give a more complex one.


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