When 78.6 g of urea ch4n2o are dissolved in 700. g of a certain mystery liquid x, the freezing point of the solution is 4.9 °c lower than the freezing point of pure x. on the other hand, when 78.6 g of sodium chloride are dissolved in the same mass of x, the freezing point of the solution is 8.5°c lower than the freezing point of pure x. calculate the van't hoff factor for sodium chloride in x. be sure your answer has a unit symbol, if necessary, and round your answer to 2 significant digits.