what is the freezing point depression with one molal of sucrose?

Answer 1

Sucrose does not have freezing point constant. This is dependent on the solvent. Assuming you are talking about water, the molar freezing point constant is 1.86 degrees Celsius. This is per mole of solute, regardless of what the solute it. Even sucrose. If you are dealing with anything but a molar solution, it is a linear relationship. Just multiply the 1.86 degrees by the molar concentration of the solution.

Answer 2

for 1 Osmole the depression of freezing point is -1.86°C

sucrose being a non-electrolyte, the depression is so -1.86°C

and the solution freezes at -1.86°C