How does adding salt to water affect the boiling point of water?
Answer Hi Dave, As soon as any of the salt dissolves in the water, the boiling point of the water will begin to rise — by about one half degree Celsius for every 58 grams of salt dissolved per kilogram of water. In fact, any non-volatile soluble substance will raise the boiling point of water. So why does the salt affect the boiling point? Here’s how boiling works The boiling point is defined as the temperature at which the saturated vapor pressure of a liquid is equal to the surrounding atmospheric pressure. For water, the vapor pressure reaches the standard sea level atmospheric pressure of 760 mmHg at 100C. Since the vapor pressure increases with temperature, it follows that for pressure greater than 760 mmHg (e.g., in a pressure cooker), the boiling point is above 100C and for pressure less than 760 mmHg (e.g., at altitudes above sea level), the boiling point will be lower than 100C. As long as a vessel of water is boiling at 760 mmHg, it will remain at 100C until the phase change
