At what temperature does pure water boil at standard atmospheric pressure (1 atm)?

• A. 212 °C
• B. 100 °C
• C. 50 °C
• D. 0 °C

Answer: (B)

Verified step by step guidance

1. Understand that the boiling point of a liquid is the temperature at which its vapor pressure equals the external pressure. For water at standard atmospheric pressure (1 atm), this is the temperature where water changes from liquid to gas.
2. Recall that standard atmospheric pressure is defined as 1 atm, which is equivalent to 760 mmHg or 101.3 kPa.
3. Know that pure water boils at 100 °C under 1 atm pressure. This is a well-established physical property of water.
4. Recognize that the other temperatures given (212 °C, 50 °C, 0 °C) do not correspond to the boiling point of water at 1 atm. For example, 212 °F is the boiling point in Fahrenheit, not Celsius.
5. Therefore, the correct boiling point of pure water at 1 atm pressure is 100 °C.