Chapter 4, Problem 4.53P

Interpretation Introduction

Interpretation:

The name and formula of the unknown alkali-metal carbonate compound is to be determined.

Concept introduction:

Precipitation reaction involves the reaction of two soluble ionic compounds to form an insoluble product. The insoluble product is known as a precipitate.

The reason for the precipitation reaction to occur is the formation of a product that is insoluble in nature. For example the reaction of alkali metal carbonate and calcium chloride to form ${\text{CaCO}}_3$.

${\text{M}}_2{\text{CO}}_3\left(aq\right)+{\text{CaCl}}_2\left(aq\right)\to {\text{CaCO}}_3\left(s\right)+2\text{MCl}\left(aq\right)$

Here, $\text{M}$ is an alkali metal. Alkali metal has $+1$ charge and carbonate has $-2$ charge. Hence, the general formula of alkali-metal carbonate is ${\text{M}}_2{\text{CO}}_3$.