Normal boiling point isa)The boiling point at 1 bar pressure.b)The boi...
The boiling point of a liquid at 1 atm is also known as the normal boiling point. It has been found that Helium has the lowest normal boiling point (−268.9 °C) because it has very weak intermolecular attractions. Liquids that have high vapour pressures and low boiling points are known to be volatile, which means they evaporate quickly at room temperature. When the temperature increases, molecules start entering the gaseous state, consequently increasing the vapor pressure of the liquid until it comes into equilibrium with the atmospheric pressure.
View all questions of this test
Normal boiling point isa)The boiling point at 1 bar pressure.b)The boi...
Understanding Normal Boiling Point
The normal boiling point of a substance is a critical concept in chemistry, particularly in thermodynamics and phase changes.
Definition of Normal Boiling Point
- The normal boiling point is defined as the temperature at which a liquid's vapor pressure equals the atmospheric pressure of 1 atmosphere (atm) or 101.3 kilopascals (kPa).
Importance of Pressure
- Boiling occurs when the vapor pressure of the liquid equals the external pressure applied to it.
- At higher pressures, the boiling point increases, while at lower pressures, the boiling point decreases.
Why Option B is Correct
- Option B states that the boiling point at 1 atm pressure is the correct definition of the normal boiling point.
- This means that under standard atmospheric conditions, the boiling point can be consistently measured and compared across different substances.
Comparison with Other Options
- Option A: The boiling point at 1 bar pressure is close to 1 atm but is not the standard definition.
- Option C: Boiling point at 2 bar pressure would be higher than the normal boiling point.
- Option D: While it describes a phase change, it lacks the essential context of pressure.
Conclusion
- Understanding the normal boiling point is essential for predicting the behavior of liquids under varying pressures and temperatures.
- Thus, the correct answer is option B, as it accurately describes the boiling point at 1 atm pressure.
Normal boiling point isa)The boiling point at 1 bar pressure.b)The boi...
1atm is considered as standard pressure at NTP
To make sure you are not studying endlessly, EduRev has designed Class 11 study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Class 11.