Question

What is the value of critical temperature of water?

• A. 647 K
• B. 312 K
• C. 346 K
• D. 493 K

Hint:

Water has exceptionally high critical constants ($T_c = 647\ \mathrm{K}$ and $P_c = 218\ \mathrm{atm}$) compared to other common small molecules like $\mathrm{CO_2}$ or $\mathrm{NH_3}$ because its extensive intermolecular hydrogen-bonding network requires an immense amount of energy to destabilize.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
We need to state the experimentally determined critical temperature (T_c) of water in Kelvin.

Step 2: Key Formula or Approach:
The critical temperature is the thermal limit beyond which a gas cannot be condensed into a liquid, no matter how high the applied pressure. Above this point, molecular kinetic energy overwhelms all intermolecular attractive forces.

Step 3: Detailed Explanation:
Water's extensive hydrogen-bonded network demands considerable thermal energy to reach its critical state. The measured T_c for water is 374°C. Converting Celsius to absolute Kelvin involves adding 273.15: T_c = 374 + 273.15 = 647.15 K, which rounds to 647 K. Among the choices listed, this aligns with 647 K.

Step 4: Final Answer:
Water's critical temperature is 647 K, option (A).