Answer:
-3 °C
Explanation:
adding salt lowers the freezing point of the water
The freezing point of the solution is -0.54°C.
ΔTf = i × Kf × m
where,
ΔTf is freezing point depression.
i is Van't Hoff factor
Kf is freezing point constant of water i.e., 1.86°Cm⁻¹
m is molality of solution
Molality is defined as the number of moles of solute per kilogram of solution.
Molality = [tex]\frac{\text{Moles of solute}}{\text{kilogram of solvent}}[/tex]
Moles of solute = [tex]\frac{\text{Given Mass}}{\text{Molar mass}}[/tex]
Molar mass of MgSO₄ = 24 + 32 + (16 × 4)
= 120 g/mol
Moles of solute = [tex]\frac{\text{Given Mass}}{\text{Molar mass}}[/tex]
= [tex]\frac{26.0}{120}[/tex]
= 0.216 mol
Put the value of moles of solute in above formula we get
Molality = [tex]\frac{\text{Moles of solute}}{\text{kilogram of solvent}}[/tex]
= [tex]\frac{0.216}{1.5}[/tex]
= 0.144 m
Van't Hoff factor for MgSO₄ is it dissociates into 1 mol Mg²⁺ and 1 mol SO₄²⁻. So Van't Hoff factor is 2.
Now,
ΔTf = i × Kf × m
= 2 × 1.86°Cm⁻¹ × 0.144
= 0.54°C
Freezing point of solution = 0°C - 0.54°C
= - 0.54°C
Thus, from the above conclusion we can say that The freezing point of the solution is -0.54°C.
Learn more about the Molality here: https://brainly.com/question/1370684
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