Under standard conditions, water boils at 212°F at what pressure?

Under standard conditions, water boils at 212°F at what pressure?

• A. 1 psi
• B. 14.696 psi
• C. 29.92 psi
• D. 5 psi

Answer: (B)

Boiling point is the temperature at which a liquid’s vapor pressure equals the surrounding pressure. At standard conditions, the surrounding pressure is defined as 1 atmosphere (sea level), which is 101.3 kPa or 14.696 psi. Under that pressure, water boils at 212°F (100°C). So the pressure corresponding to standard boiling is 14.696 psi (often rounded to about 14.7 psi). The other pressures listed are not standard atmospheric pressure, so they don’t match the 212°F boiling point.

Boiling point is the temperature at which a liquid’s vapor pressure equals the surrounding pressure. At standard conditions, the surrounding pressure is defined as 1 atmosphere (sea level), which is 101.3 kPa or 14.696 psi. Under that pressure, water boils at 212°F (100°C). So the pressure corresponding to standard boiling is 14.696 psi (often rounded to about 14.7 psi). The other pressures listed are not standard atmospheric pressure, so they don’t match the 212°F boiling point.