We need to mention 'atmospheric pressure' in the definition of boiling point because the boiling point is the temperature at which a liquid's vapor pressure equals the external pressure. Atmosp

Q7.

1. We need to mention 'atmospheric pressure' in the definition of boiling point because the boiling point is the temperature at which a liquid's vapor pressure equals the external pressure. Atmospheric pressure is the standard external pressure, so it must be specified for a consistent definition.
2. If the pressure is less than atmospheric pressure, water will boil at a lower temperature. This occurs because less vapor pressure is required to overcome the reduced external pressure, allowing boiling to happen at a lower temperature.