Understanding Electrical Conductivity in Solutions

Electrical conductivity in a solution depends on the presence of mobile charge carriers, which are typically ions. When substances that can dissociate into ions are dissolved in water, the resulting solution can conduct electricity. These substances are called electrolytes. Substances that dissolve but do not dissociate into ions form non-electrolytes, and their solutions do not conduct electricity.

Analyzing Conductivity of Different Solutions

Let's examine each option to determine whether the substance dissolves to form ions or remains as neutral molecules.

• Sodium Hydroxide Solution: Sodium hydroxide ($\text{NaOH}$) is a strong base and an ionic compound. When dissolved in water, it dissociates completely into sodium ions ($\text{Na}^+$) and hydroxide ions ($\text{OH}^-$). The presence of these mobile ions allows the solution to conduct electricity.

  $\text{NaOH(s)} \xrightarrow{\text{H}_2\text{O}} \text{Na}^+\text{(aq)} + \text{OH}^-\text{(aq)}$

• Glucose Solution: Glucose ($\text{C}_6\text{H}_{12}\text{O}_6$) is a sugar, which is a covalent compound. When glucose dissolves in water, the molecules spread out but do not break apart into ions. The solution contains neutral glucose molecules and water molecules, but no significant number of mobile charge carriers. Therefore, glucose solution does not conduct electricity.

  $\text{C}_6\text{H}_{12}\text{O}_6\text{(s)} \xrightarrow{\text{H}_2\text{O}} \text{C}_6\text{H}_{12}\text{O}_6\text{(aq)}$

• Acetic Acid Solution: Acetic acid ($\text{CH}_3\text{COOH}$) is a weak acid. When dissolved in water, it undergoes partial dissociation to form acetate ions ($\text{CH}_3\text{COO}^-$) and hydrogen ions ($\text{H}^+$) (which exist as hydronium ions, $\text{H}_3\text{O}^+$, in water). Because it's a weak acid, the dissociation is not complete, but there are enough ions present to allow the solution to conduct electricity, although less efficiently than strong electrolytes.

  $\text{CH}_3\text{COOH(aq)} + \text{H}_2\text{O(l)} \rightleftharpoons \text{CH}_3\text{COO}^-\text{(aq)} + \text{H}_3\text{O}^+\text{(aq)}$

• Hydrochloric Acid Solution: Hydrochloric acid ($\text{HCl}$) is a strong acid. When dissolved in water, it dissociates almost completely into hydrogen ions ($\text{H}^+$) and chloride ions ($\text{Cl}^-$). The presence of these mobile ions allows the solution to conduct electricity effectively.

  $\text{HCl(aq)} + \text{H}_2\text{O(l)} \rightarrow \text{H}_3\text{O}^+\text{(aq)} + \text{Cl}^-\text{(aq)}$

Comparison of Solution Conductivity

We can summarize the conductivity of these solutions based on their ability to form ions:

Based on this analysis, glucose solution is the only one among the options that does not form ions in water and therefore does not conduct electricity.

Conclusion on Non-Conducting Solutions

The solution that does not conduct electricity among the given options is glucose solution, because glucose is a non-electrolyte and dissolves in water without forming mobile ions.

Revision Table: Electrolytes and Conductivity

Additional Information on Electrolyte Types

Electrolytes are classified based on the extent of their dissociation in water:

• Strong Electrolytes: Dissociate completely or nearly completely into ions. Examples include strong acids ($\text{HCl}, \text{HNO}_3, \text{H}_2\text{SO}_4$), strong bases ($\text{NaOH}, \text{KOH}, \text{Ca(OH)}_2$), and most soluble salts ($\text{NaCl}, \text{KCl}, \text{MgSO}_4$). Their solutions are good conductors of electricity.
• Weak Electrolytes: Dissociate only partially into ions. An equilibrium exists between the undissociated molecule and the ions. Examples include weak acids ($\text{CH}_3\text{COOH}, \text{H}_2\text{CO}_3, \text{HF}$) and weak bases ($\text{NH}_3, \text{C}_6\text{H}_5\text{NH}_2$). Their solutions are poor conductors of electricity compared to strong electrolytes because fewer ions are available.
• Non-electrolytes: Do not dissociate into ions when dissolved in water. They exist as neutral molecules in solution. Examples include glucose ($\text{C}_6\text{H}_{12}\text{O}_6$), sucrose ($\text{C}_{12}\text{H}_{22}\text{O}_{11}$), ethanol ($\text{C}_2\text{H}_5\text{OH}$), and urea ($\text{CO(NH}_2)_2$). Their solutions do not conduct electricity.