Q. 9.13 - An Introduction to General, Organic, and Biological Chemistry

Question

Classify the solute represented in each of the following equations as a strong, weak, or nonelectrolyte:

a. ${\mathrm{K}}_2{\mathrm{SO}}_4\left(s\right)\stackrel{{\mathrm{H}}_2\mathrm{O}}{⟶}2{ \mathrm{K}}^{+}\left(aq\right)+{\mathrm{SO}}_4^{2-}\left(aq\right)$

b. ${\mathrm{NH}}_3\left(g\right)+{\mathrm{H}}_2\mathrm{O}\left(l\right)\rightleftarrows {\mathrm{NH}}_4^{+}\left(aq\right)+{\mathrm{OH}}^{-}\left(aq\right)$

c. ${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(s\right)\stackrel{{\mathrm{H}}_2\mathrm{O}}{⟶}{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(aq\right)$

Step-by-Step Solution

Answer

(part a) The following equation ${\mathrm{K}}_2{\mathrm{SO}}_4\left(s\right)\stackrel{{\mathrm{H}}_2\mathrm{O}}{⟶}2{ \mathrm{K}}^{+}\left(aq\right)+{\mathrm{SO}}_4^{2-}\left(aq\right)$ is a strong electrolyte.

(part b) The equation ${\mathrm{NH}}_3\left(g\right)+{\mathrm{H}}_2\mathrm{O}\left(l\right)\rightleftarrows {\mathrm{NH}}_4^{+}\left(aq\right)+{\mathrm{OH}}^{-}\left(aq\right)$ is an example of weak electrolyte.

(part c) The next equation ${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(s\right)\stackrel{{\mathrm{H}}_2\mathrm{O}}{⟶}{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(aq\right)$ is a non-electrolyte.

Step1: Introduction (part a)

A solution is a relatively homogenous system which contains two or more substances. Generally, we come up with a solution as a liquid containing some disintegrated material, including a liquid, solid or gas, but solutions of one solid in the other are also common, with an alloy of gold and silver being one example.

Step2: Explain Strong, Weak and Non-Electrolyte (part a)

Strong electrolytes exhibit the following properties: They are composed of ionic compounds that, when mixed with water, completely separate into their ions and ionize in solution due to the presence of ions, but not in solid form because neutral particles do not conduct anything.

Weak electrolytes appear to be highly ionized water substances. Strong electrolytes are generally alkaline and base, whereas weak electrolytes are acidic and base.

A non-electrolyte material doesn't really undergo oxidation once absorbed in a solution. 

Step3: Find the given equation strong, weak or non-electrolyte (part a).

$K_{2}S{O}_4$ is a strong electrolyte because it has the following properties:

They are composed of ionic compounds, and then when dissolved in water, they completely separate into their ions. They store energy in solution due to the combination of ions, rather than in solid form, because neutral molecules do not conduct electricity.

Therefore,

${\mathrm{K}}_2{\mathrm{SO}}_4\left(s\right)\stackrel{{\mathrm{H}}_2\mathrm{O}}{⟶}2{ \mathrm{K}}^{+}\left(aq\right)+{\mathrm{SO}}_4^{2-}\left(aq\right)$is a strong electrolyte.

Step4: Find the given equation strong, weak or non-electrolyte (part b).

${\mathrm{NH}}_3\left(g\right)+{\mathrm{H}}_2\mathrm{O}\left(l\right)\rightleftarrows {\mathrm{NH}}_4^{+}\left(aq\right)+{\mathrm{OH}}^{-}\left(aq\right)$

Hence, $N{H}_3$ partially ionizes in water, it is an example of a weak electrolyte.

Step5: Find the given equation strong, weak or non-electrolyte (part c).

${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(s\right)\stackrel{{\mathrm{H}}_2\mathrm{O}}{⟶}{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(aq\right)$

$C_2{H}_{12}{O}_6$ is an example of a nonelectrolyte since it does not oxidize when dispersed in a solution.