Gunnison Bay, the north arm of Great Salt Lake in Utah has a roughly constant salinity of about 28%. In other words, 100 g of water from Gunnison Bay consists of 28 g of salt and 72 g of water.
A. Let's assume that all of the salt in Gunnison Bay is sodium chloride, NaCl, and that we can ignore any molecular solutes (for example, dissolved gases). The coldest day on record for Salt Lake City is -30°F. on February 9. 1933. That's -34°C (you're welcome). Calculate the freezing point temperature of water taken from Gunnison Bay. For water. Kf = 1.86 °C/m and Kb = 0.52 °C/m.
B. The assumption we made in Part A is not a very good one. The salt includes a number of other compounds besides NaCl. Assuming the only other major component is MgCl2, will the freezing point be higher or lower than what you calculated in Part A?