Question

$K_{2}C{O}_3\left(aq\right)+Ca{\left(OH\right)}_2\left(aq\right)\to {\mathrm{CaCO}}_3\downarrow \left(s\right)+2\mathrm{KOH}\left(\mathrm{aq}\right)$

The above reaction is an example of ______ reaction and the precipitate formed in this reaction is ______ .

• A. combination, KOH
• B. combination, CaCO${}_3$
• C. double displacement, KOH
• D. double displacement, CaCO${}_3$

Answer 1

The correct option is D double displacement, CaCO${}_3$

The given reaction is a double displacement reaction since the reactants $K_{2}C{O}_3$ and $Ca(OH{)}_2$ are exchanging their ions $C{O}_3^{2-}$ and $O{H}^{-}$ with each other in order to form $CaC{O}_3$ and $KOH$ as products.

This is also a precipitation reaction since the $CaC{O}_3$ formed here is an insoluble white coloured precipitate.