Consider the following aqueous solutions and assume 100% ionization in...
Consider the following aqueous solutions and assume 100% ionization in...
Explanation:
The freezing point depression and boiling point elevation of a solution depend on the number of solute particles in the solution. The greater the number of solute particles, the greater the effect on the colligative properties of the solution.
1. 0.1 m urea: Urea is a non-electrolyte and does not dissociate into ions in water. Therefore, it does not increase the number of solute particles in the solution. Hence, the freezing point depression and boiling point elevation will be the least for this solution.
2. 0.04 m Al2(SO4)3: Aluminum sulfate dissociates into three ions (2Al3+ and 3SO42-) in water. Therefore, it increases the number of solute particles in the solution. Hence, the freezing point depression and boiling point elevation will be higher than solution 1.
3. 0.05 m CaCl2: Calcium chloride dissociates into three ions (1Ca2+ and 2Cl-) in water. Therefore, it increases the number of solute particles in the solution. Hence, the freezing point depression and boiling point elevation will be higher than solution 1 and 2.
4. 0.005 m NaCl: Sodium chloride dissociates into two ions (1Na+ and 1Cl-) in water. Therefore, it increases the number of solute particles in the solution. Hence, the freezing point depression and boiling point elevation will be higher than solution 1 but lower than solution 2 and 3.
Therefore, the correct statement regarding the above solutions is that the vapour pressure will be highest for solution 2 as it has the highest number of solute particles. Higher the number of solute particles, the lower the vapour pressure.