Follwing are equimolal aqueous solution:
a.`1 m urea` , b.`1 m KCl` , c.`1 m MgCl_(2)` , d.`1 m Na_(3)PO_(4)`
Arrange them in increaseing
i. Boiling point , ii.Freezing point , iii. Osmotic pressure , iv.Vapour pressure

Explanation

While analysing the colligative properties, if the density of the solution is not given, take the Molarity of the solution same as Molality and vice-versa.
In such type of questions, always assume 100% dissociation for the ionic solutes until and unless specified.
`{:("Solute", "lonisation",i),("Urea",No,1),(KCl,K^(+)+Cl-,2),(MgCl_2,Mg^(2+)+2Cl^-,3),(Na_3PO_4,3Na^(+)+PO_4^(3-),4):}`
Freezing point of solution
`T_f =T_f^0-(DeltaT_f)`
`Delta T_f =i (K_fm )`
Thus , greater the value, of `DeltaT_f` but smaller the value of freezing point.
`D lt C lt B lt A `