What is the boiling point of water as measured on a Celsius thermometer at standard atmospheric pressure?

• A. 100
• B. 373
• C. 212
• D. 0

Answer: (A)

Verified step by step guidance

1. Understand that the boiling point of a substance is the temperature at which its vapor pressure equals the external pressure. For water at standard atmospheric pressure (1 atm), this is a well-known reference point.
2. Recall that standard atmospheric pressure is defined as 1 atmosphere (atm), which is equivalent to 101.3 kPa or 760 mmHg.
3. Know the boiling point of water at 1 atm pressure is commonly used as a fixed point in temperature scales, especially the Celsius scale.
4. Recognize that on the Celsius scale, the boiling point of pure water at 1 atm is defined as 100 degrees Celsius.
5. Therefore, the boiling point of water measured on a Celsius thermometer at standard atmospheric pressure is 100°C.