At a vacuum of 2000 Microns, what is the boiling point of water?

• A. 0°C
• B. -9.66°C
• C. 25°C
• D. 100°C

Answer: (B)

At a vacuum of 2000 microns, the boiling point of water is approximately -9.66°C. This phenomenon occurs due to the relationship between pressure and boiling point: the lower the pressure, the lower the boiling point. Standard atmospheric pressure at sea level allows water to boil at 100°C, but as pressure decreases, water requires less thermal energy to enter its gaseous state.

At about 2000 microns of mercury (Hg), which is much lower than the standard pressure, water can boil at temperatures well below freezing. Specifically, around this vacuum pressure, it is around -9.66°C, indicating that water will transition to vapor at this temperature. Understanding this principle is crucial in fields like refrigeration and HVAC, where managing pressure and temperature is vital for effective system operation.