At what temperature does pure water freeze under standard atmospheric pressure?

• A. 0 °C
• B. 32 °C
• C. -273 °C
• D. 100 °C

Answer: (A)

Verified step by step guidance

1. Understand that the freezing point of a substance is the temperature at which it changes from liquid to solid under a given pressure, typically standard atmospheric pressure (1 atm).
2. Recall that pure water has a well-known freezing point under standard atmospheric pressure, which is a fundamental physical property.
3. Recognize that the freezing point of pure water is commonly used as a reference point in temperature scales, such as Celsius.
4. Identify that the freezing point of pure water under standard atmospheric pressure is 0 °C.
5. Confirm that the other temperature options (32 °C, -273 °C, 100 °C) correspond to different physical phenomena: 32 °C is above freezing, -273 °C is absolute zero, and 100 °C is the boiling point of water at 1 atm.