Which aqueous solution would possess the highest boiling point?
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Answer: C. 0.15 m CaCl2
Explanation
Calcium chloride dissociates into three distinct ions per formula unit upon dissolving in water. Multiplying its molality by this van 't Hoff factor yields the highest total solute particle concentration. Greater particle concentration causes a larger boiling point elevation compared to solutions with fewer ions. Boiling point elevation is a colligative property dependent on the total concentration of dissolved particles. The calculation multiplies molality by the ebullioscopic constant and the number of dissociated ions. Electrolytes produce multiple ions, increasing the effective particle molality beyond the nominal solute concentration.
This principle explains why adding salt to cooking water raises its boiling temperature slightly during cooking. Automotive engineers apply boiling point elevation concepts when formulating engine coolants and antifreeze mixtures. Measuring boiling point changes allows chemists to determine unknown molar masses of non-volatile solutes. Glucose is a non-electrolyte that does not dissociate, resulting in a lower particle concentration and boiling point. Sodium chloride dissociates into two ions, yielding a smaller particle concentration than the calcium chloride solution. Sucrose is a large molecular non-electrolyte that provides insufficient particle concentration to match calcium chloride.
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