Answer: The melting point of water is lowered by 1.85 degrees Celsius if 29.2 grams of salt are dissolved in each Kg of water (called a "0.5 molal solution" of salt). So normal saline, a 0.9 molal solution), is lowered juts less than twice this or 3.33 deg C.
So normal saline freezes at -3.33 deg C or 26 deg F.
Answer: Plants will not grow well in a saline solution because it will dehydrate the plant, unless the plant is a type of mangrove or is salinity tolerant. Plants may grow better in sugar water (provided there is not too much) because plants can use the sugars to build more cellulose and grow. Regular water will maintain the Status Quo.
Answer: Normal saline is a solution of 9 grams of sodium chloride ( salt) in solution. The solute is one liter of water. Normal refers to the concentration of salt to water. Other concentrations include half normal or quarter normal saline. In medical uses this solution is used in a sterile formulation for Intravenous infusions, medicated dressings, eye and bladder irrigation and wound lavage and skin cleansing.
Answer: Normal Saline should not be used in the humidifier of your CPAP machine. Only distilled water should be used. The salt in the saline water could build up in the water chamber and introduce bacteria in the air your breathe. If you have further questions regarding this, you should speak with your physician or respiratory therapist.