The van't Hoff factor $$i$$ for a compound which undergoes dissociation in one solvent and association in other solvent is respectively

A solution of sucrose (molar mass = 342 g mol^$$-$$) has been prepared by dissolving 68.5 g of sucrose in 1000 g of water. The freezing point of the solution obtained will be (K_f for water = 1.86 K kg mol^$$-$$1)

An aqueous solution is 1.00 molal in KI. Which change will cause the vapour pressure of the solution to increase?

A 0.0020 m aqueous solution of an ionic compound [Co(NH₃)₅(NO₂)]Cl freezes at $$-$$ 0.00732^oC. Number of moles of ions which 1 mol of ionic compound produces on being dissolved in water will be (K_f = $$-$$1.86^oC/m)