A certain substance X has a normal freezing point of -10.1 degree C and a molal freezing point depression constant K_f = 5.32 degree C middot kg middot mol^-1. Calculate the freezing point of a solution made of 29.82 g of urea ((NH_2)_CO) dissolved in 500. g of X. Be sure your answer has the correct number of significant digits.

Explanation:

where,

= boiling point of solution = ?

= boiling point of solvent (X) =

= freezing point constant  =

m = molality

i = Van't Hoff factor = 1 (for non-electrolyte like urea)

= mass of solute (urea) = 29.82 g

= mass of solvent (X) = 500.0 g

= molar mass of solute (urea) = 60 g/mol

Now put all the given values in the above formula, we get:

Therefore, the freezing point of  solution is

c.

explanation: