Answer:
O begins to boil
Step-by-step explanation:
When the vapor pressure of a liquid is equal to the atmospheric pressure, the liquid suddenly begins to boil.
- At this point the boiling point of the liquid has been reached.
- Further addition of heat energy will cause the liquid to boil vigorously
- Subsequently evaporation will start from the surface of the boiling liquid.
- The atmospheric pressure is the ambient pressure measured with the respect to the sea level pressure.