Q. 9.31 - An Introduction to General, Organic, and Biological Chemistry

Question

Predict whether each of the following ionic compounds is soluble in water:

a. $LiCl$

b. $PbS$

c. $BaC{O}_3$

d. $K_{2}O$

e. $Fe{\left(N{O}_3\right)}_3$

Step-by-Step Solution

Answer

(part a) The ionic compound $LiCl$ is soluble in water.

(part b) The ionic compound $PbS$ is insoluble in water.

(part c) The ionic compound $BaC{O}_3$ is insoluble in water.

(part d) The ionic compound $K_{2}O$ is soluble in water.

(part e) The ionic compound $Fe{\left(N{O}_3\right)}_3$ is soluble in water.

Step1: Introduction (part a).

If an ionic compound contains one of the following ions, it is soluble in water:

Positive ions: ${\mathrm{Li}}^{+},{\mathrm{Na}}^{+},{\mathrm{K}}^{+},{\mathrm{Rb}}^{+},{\mathrm{Cs}}^{+},{\mathrm{NH}}_4^{+}$.

Negative ions: ${\mathrm{NO}}_3^{-},{\mathrm{C}}_2{\mathrm{H}}_3{\mathrm{O}}_2^{-},{\mathrm{Cl}}^{-},{\mathrm{Br}}^{-},{\mathrm{I}}^{-}$

Step2: Given Information (part a).

Given:

$LiCl$

Step3: Explanation (part a).

$L{i}^{+}$ and $C{l}^{-}$ ions are present in the ionic compound $LiCl.$

Hence, $LiCl$ is soluble in water.

Step4: Given Information (part b).

Given:

$PbS$

Step5: Explanation (part b).

$P{b}^{2+}$and $S^{2-}$ions are present in the ionic compound $PbS.$The majority of sulphide containing $S^{2-}$ ions are insoluble. As a result, $PbS$ is insoluble in water.

Step6: Given Information (part c).

Given:

$BaC{O}_3$

Step7: Explanation (part c).

The ionic compound $BaC{O}_3$ contains $B{a}^{2+}$ and $C{O_3}^{2-}$ ions. Carbonates with $C{O_3}^{2-}$ ions are insoluble in water. For this reason, $BaC{O}_3$ is insoluble in water.

Step8: Given Information (part d).

Given:

$K_{2}O$

Step9: Explanation (part d).

$K_{2}O$ is an ionic compound that contains $K^{+}$ ions. In water, $K^{+}$ ions are always soluble. As a result, $K_{2}O$ is soluble in water.

Step10: Given Information (part e).

Given:

$Fe{\left(N{O}_3\right)}_3$

Step11: Explanation (part e).

$Fe{\left(N{O}_3\right)}_3$ is soluble in water because the ions present in this always soluble in water.