Chapter 11, Problem 4STP

Interpretation Introduction

Interpretation : The contents of each dropper bottle are to be identified.

Concept Introduction : An aqueous solution is one in which water serves as the solvent. Chemical equations typically illustrate it by adding to the appropriate chemical formula.

Answer to Problem 4STP

The content of dropper bottle P is calcium nitrate.

The content of dropper bottle Q is potassium carbonate.

The content of dropper bottle R is hydrochloric acid.

Explanation of Solution

Consider the given three aqueous solutions: Potassium carbonate, hydrochloric acid, and calcium nitrate.

Potassium carbonate $\left({\text{K}}_{\text{2}}{\text{CO}}_{\text{3}}\right)$ is soluble in water and is a salt.

Hydrochloric acid $\left(\text{HCl}\right)$ is very soluble in water and is a strong acid.

Calcium nitrate $\left(\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\right)$ is soluble in water and is a salt.

When potassium carbonate reacts with hydrochloric acid, carbon dioxide gas is produced.

  ${\text{K}}_{\text{2}}{\text{CO}}_{\text{3}}\left(aq\right)+\text{2HCl}\left(aq\right)\to {\text{CO}}_{\text{2}}\left(g\right)+\text{2KCl}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)$

When calcium nitrate reacts with hydrochloric acid, there is no reaction.

When potassium carbonate reacts with calcium nitrate, there is the formation of a precipitate of calcium carbonate.

  ${\text{K}}_{\text{2}}{\text{CO}}_{\text{3}}\left(aq\right)+\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\left(aq\right)\to {\text{CaCO}}_3\left(s\right)+{\text{KNO}}_3\left(aq\right)$

The solution R is hydrochloric acid since it forms gas with Q (potassium carbonate) and there is no reaction with P (calcium nitrate).

The solution P is calcium nitrate which forms a precipitate with Q.