Asolution of water (kf=1.86 ∘c/m) and glucose freezes at − 4.15 ∘c. what is the molal concentration of glucose in this solution? assume that the freezing point of pure water is 0.00 ∘c.

The formula for depression of freezing point is:

   -(1)

where, is depression of freezing point, is freezing point depression constant and is molality.

Freezing point of pure water =  (given)

Freezing point of glucose =  (given)

Depression of freezing point, =

Substituting the values:

Substituting the values in formula (1):

Hence, the the molal concentration of glucose in the given solution is .