Select most correct option . At high altitude, the boiling point of water decreases because there atmospheric__________.

The correct answer is pressure is low.

Key Points

• At high altitudes, the atmospheric pressure is significantly lower compared to sea level.
• Lower atmospheric pressure reduces the boiling point of water because the molecules require less energy to escape into the vapor phase.
• For example, at sea level (1 atm pressure), water boils at 100°C, but at higher altitudes, such as 2,500 meters above sea level, it may boil at approximately 92°C.
• This phenomenon is crucial for cooking and various scientific calculations, as it affects the time and temperature needed for boiling.

Additional Information

• Atmospheric Pressure:
  • Atmospheric pressure is the force exerted by the weight of air above a surface in the atmosphere of Earth.
  • It decreases with altitude because there are fewer air molecules exerting pressure as one goes higher.
• Boiling Point:
  • The boiling point is the temperature at which a liquid's vapor pressure equals the external pressure surrounding the liquid.
  • When external pressure decreases, the boiling point of the liquid decreases.
• Vapor Pressure:
  • Vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature.
  • It increases with temperature.
• Altitude Effects:
  • People living at high altitudes often use pressure cookers to compensate for lower boiling points, ensuring that food cooks properly.
  • Mountaineers and pilots need to consider these effects for both personal health and equipment functionality.