Question

The glass transition temperature of water is:

• A. -135°C
• B. -35°C
• C. -235°C
• D. 35°C

Hint:

Remember that the glass transition temperature for water is significantly lower than its melting point and is an important consideration in materials science and cryobiology.

Answer 1

The Correct Option is C

Step 1: Concept
The glass transition temperature (Tg) is the temperature at which a material changes from a rigid, brittle state to a more amorphous and rubbery state without going through a liquid phase. For many polymers, this temperature is well below their melting point.

Step 2: Meaning
For water, the glass transition temperature refers to the specific temperature where its structure transitions from an ordered crystalline form (ice) to a disordered amorphous solid or supercooled liquid state without passing through a conventional liquid phase.

Step 3: Analysis
Water has a unique behavior compared to most other substances due to hydrogen bonding. The Tg of water is significantly lower than the melting point of ice, which is 0°C (273.15 K). At -135°C (-210°F), water can exist in an amorphous solid state known as glassy water or supercooled water. - Option A: -135°C This temperature is consistent with the reported Tg of water, making it a plausible candidate. - Options B and D: -35°C and 35°C are much higher than the typical Tg of water and do not represent its glass transition behavior accurately. - Option C: -235°C This temperature is extremely low and far below any known glass transition temperature for water. It would be more relevant to discuss the absolute zero point in this context, which is -273.15°C (-459.67°F).

Step 4: Conclusion
The correct Tg of water is around -135°C. Final Answer: (C)