Question

Which (if any) of the following compounds are electrolytes? (a) glucose, \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\) (b) ethanol, \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\). (c) magnesium sulfide, \(\mathrm{MgS}\). (d) sulfur hexafluoride, \(\mathrm{SF}_{6}\).

Short answer

a) glucose (\(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\)), b) ethanol (\(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\)), c) magnesium sulfide (\(\mathrm{MgS}\)), or d) sulfur hexafluoride (\(\mathrm{SF}_{6}\))? Answer: Magnesium sulfide (\(\mathrm{MgS}\)) is an electrolyte.

Step-by-step solution

(a) Analyzing glucose, \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\)

Glucose is a simple carbohydrate with the molecular formula \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\). As glucose is a sugar, it can dissolve in water to form a solution, but it does not dissociate into ions able to conduct electricity. Hence, glucose is not an electrolyte.

(b) Analyzing ethanol, \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\)

Ethanol is an alcohol with the molecular formula \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\). Although ethanol dissolves in water, it does not dissociate into ions that can conduct electricity. Therefore, ethanol is not an electrolyte.

(c) Analyzing magnesium sulfide, \(\mathrm{MgS}\)

Magnesium sulfide is an ionic compound with the molecular formula \(\mathrm{MgS}\). When dissolved in water, it dissociates into magnesium cations (\(\mathrm{Mg}^{2+}\)) and sulfide anions (\(\mathrm{S}^{2-}\)), both of which can conduct electricity. Therefore, magnesium sulfide is an electrolyte.

(d) Analyzing sulfur hexafluoride, \(\mathrm{SF}_{6}\)

Sulfur hexafluoride is a covalent compound with the molecular formula \(\mathrm{SF}_{6}\). Sulfur hexafluoride does not dissolve in water, and it does not dissociate into ions that can conduct electricity. Hence, sulfur hexafluoride is not an electrolyte. To summarize, only magnesium sulfide (\(\mathrm{MgS}\)) is an electrolyte among the given compounds.

Key concepts

Glucose

Glucose, with the chemical formula \( \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6} \), is a type of sugar that plays a crucial role as an energy source in biological systems. Despite being soluble in water, glucose does not dissociate into ions. This means that, although it can form solutions, it cannot conduct electricity when dissolved.

As a result, glucose is not classified as an electrolyte. Electrolytes are substances that produce free-moving ions when dissolved in a solvent, and these ions carry electric current. Because glucose remains intact in solution without forming ions, it is considered a non-electrolyte.

• Solubility: High in water
• Dissociation: None
• Electrolyte Status: No

Ethanol

Ethanol, known chemically as \( \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH} \), is a common alcohol often found in alcoholic beverages and used as a solvent. Like glucose, ethanol is soluble in water, indicating that it can form homogeneous solutions.

However, ethanol does not dissociate into ions when it dissolves, which means it cannot conduct electricity. Thus, ethanol is not considered an electrolyte. The lack of ion production in solution renders ethanol similar to glucose in its inability to transport electric charges.

• Solubility: High in water
• Dissociation: None
• Electrolyte Status: No

Magnesium Sulfide

Magnesium sulfide, or \( \mathrm{MgS} \), represents an example of an ionic compound. These compounds consist of metals and nonmetals that create an ionic bond by transferring electrons.

In the case of magnesium sulfide, when it is dissolved in water, it dissociates into magnesium ions \( \mathrm{Mg}^{2+} \) and sulfide ions \( \mathrm{S}^{2-} \). These ions are able to freely move in the solution, thus allowing it to conduct electricity. This characteristic designates magnesium sulfide as an electrolyte.

• Solubility: Dissociates in water
• Dissociation: Into \( \mathrm{Mg}^{2+} \) and \( \mathrm{S}^{2-} \)
• Electrolyte Status: Yes

Ionic Compounds

Ionic compounds are formed from the bonding of metals and nonmetals through the transfer of electrons, which generate oppositely charged ions. These ions are held together by strong electrostatic forces known as ionic bonds.

When ionic compounds dissolve in water, they generally dissociate into their respective ions. This dissociation process is key in the functionality of many ionic compounds as electrolytes. The free-moving ions produced in solution allow the compound to conduct electricity efficiently.

Examples of ionic compounds include magnesium sulfide \( \mathrm{MgS} \). They contrast with covalent compounds, such as glucose and ethanol, which do not dissociate in water.

• Formation: Metal and Nonmetal
• Main bond: Ionic
• Characteristic: Dissociate in solution to conduct electricity