Question

At high altitudes, water boils at a lower temperature because

• A. the atmospheric pressure is high at high altitudes
• B. the viscosity of water is reduced at high altitudes
• C. the atmospheric pressure is low at high altitudes
• D. the surface tension of water is reduced at high altitudes

Answer 1

Answer: (C)

the atmospheric pressure is low at high altitudes

The boiling of water depends on the atmospheric pressure at that altitude. At high altitudes, the pressure is lower, so water can not boil at $100°$. As the altitude increases, the boiling point of water reduces.