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Question
Water boils at 120 °C in a pressure cooker. Explain the reason.
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Solution
- The boiling point of a liquid rises with increased pressure and falls with decreased pressure. At one atmosphere pressure, pure water has a boiling point of 100°C.
- A pressure cooker does not allow steam to escape. Because of the increased pressure, the vapor pressure on the water inside the cooker rises to approximately 1.75 times that of the atmosphere, causing water to boil at around 120°C to 125°C.
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