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Question #44530
The Question
A sample of sucrose () is dissolved in of water. A trace amount of an acid catalyst is added, and the solution is heated until the inversion of sucrose is complete. The resulting monosaccharides undergo mutarotation and reach their respective anomeric equilibria. For D-glucose, the equilibrium mixture contains -anomer and -anomer. For D-fructose, the equilibrium mixture contains -pyranose, -furanose, and -furanose. Assuming the trace acid contributes negligibly to the molality, what is the boiling point elevation () of the final solution? ( for water = , Molar mass of sucrose = , Molar mass of water = )
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Mechanism_Trap
Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.
Concepts Behind This Question
Boiling Point Elevation (Solvent vs Solution)|Van’t Hoff Factor (i) Application|D-Glucose Anomeric Equilibrium
Why This Question Is Tricky
Common Mistakes
The problem tests two major hidden traps.
First, the 'Chemical Exception' of mutarotation: students often incorrectly assume that anomeric equilibrium implies dissociation or creation of new particles, leading to an erroneous Van't Hoff factor ().
In reality, isomerization does not change the total moles of solute.
Second, the 'Hidden Variable' of solvent consumption: during the hydrolysis (inversion) of sucrose, water acts as a reactant.
Failing to subtract the mass of consumed water () from the solvent mass leads to the incorrect molality and the trap answer of .
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Solutions - Class 12 |
| Concept | Boiling Point Elevation (Solvent vs Solution) |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |