Chapter 18, Problem 126A

Interpretation Introduction

Interpretation: The substance from the given substances that readily dissolves in water is to be identified.

Concept introduction: Solubility is the maximum amount of a chemical that will dissolve in a given quantity of solvent at a particular temperature. Solubility is a defining characteristic of a particular solute-solvent combination, and the solubilities of various compounds vary considerably.

Answer to Problem 126A

From the given substances, (b) ${\text{C}}_2{\text{H}}_6\left(g\right)$ is the only substance that readily dissolves in water.

Explanation of Solution

The given substances are as follows:

1. $\text{KI}\left(s\right)$
2. ${\text{C}}_2{\text{H}}_6\left(g\right)$
3. ${\text{NH}}_{\text{4}}\text{Cl}\left(s\right)$
4. ${\text{Na}}_3{\text{PO}}_4\left(s\right)$

The solubility of a solid increases while the solubility of a gas decreases as temperature increases. Ethane is the only gaseous substance among the four mentioned substances. Therefore, only (b) ${\text{C}}_2{\text{H}}_6\left(g\right)$ readily dissolves in water.

Conclusion

From the given substances, (b) ${\text{C}}_2{\text{H}}_6\left(g\right)$ is the only substance that readily dissolves in water.