Final answer:
The sodium chloride (NaCl) solution is expected to have the lowest freezing point among the given options because it dissociates into two particles per formula unit, significantly lowering the freezing point due to the colligative property of freezing point depression.
Step-by-step explanation:
The question asks to determine which aqueous solution among Sodium chloride (NaCl), Glucose (C₆H₁₂O₆), Ethanol (C₂H₅OH), and Sucrose (C₁₂H₂₂O₁₁) is expected to have the lowest freezing point. The principle that governs the freezing point of solutions is colligative properties, specifically the freezing point depression. Freezing point depression occurs because the presence of solute particles disrupts the formation of a solid phase, lowering the temperature at which the liquid will freeze.
Sodium chloride (NaCl) dissociates into two particles, Na+ and Cl-, thereby effectively doubling the number of solute particles in the solution, compared to a non-electrolyte like glucose or sucrose, which do not dissociate. Ethanol, being a covalent compound, will largely remain undissociated. Thus, of the four choices, the sodium chloride solution is expected to have the lowest freezing point because it produces more solute particles per mole, inducing a greater freezing point depression.