Which of the following solutions has higher freezing point?

0.05 M Al₂(SO₄)₃, 0.1 M K₃[Fe(CN)₆] Justify.

For 0.05 M Al₂(SO₄)₃

Dissociation of Al₂(SO₄)₃

Al₂(SO₄)₃ → 2Al³⁺ + 3SO₄^2-

∴ i = 5

Where i is the actual no. of particles after dissociation

To find out the freezing point, we apply the formula:

ΔT_f = i × concentration

As concentration = 0.05 M (given)

∴ ΔT_f = 5 × 0.05M

⇒ ΔT_f = 0.25 moles of ions

For 0.1 M K₃[Fe(CN)₆]

Dissociation of K₃[Fe(CN)₆]

K₃[Fe(CN)₆] → 3K⁺ + [Fe(CN)₆]^3-

∴ i=3

Where i is the actual no. of particles after dissociation

To find out the freezing point, we apply the formula:

ΔT_f = i × concentration

As concentration = 0.1 M (given)

∴ ΔT_f = 4 × 0.1M

⇒ ΔT_f = 0.4 moles of ions

The higher the T_f value, the lower the freezing point. Hence, 0.05 M Al₂(SO₄)₃ has higher freezing point.