Answer:
The solutions are listed from the lowest freezing point to highest freezing point.
Mgā(POā)ā - Ā AlBrā - BeBrā - Ā KBr
Explanation:
Colligative property of freezing point, is the freezing point depression.
Formula is:
ĪT = Kf . m . i
Where ĪT = TĀ° freezing pure solvent - TĀ° freezing solution
Kf is the cryoscopic constant
m is molality and i is the Van't Hoff factor (number of ions, dissolved in solution)
In this case, TĀ° freezing pure solvent is 0Ā° because it's water, so the Kf is 1.86 Ā°C/m, and m is 0.1 molal.
The i modifies the TĀ° freezing solution. The four salts, are ionic compounds, so for each case:
BeBrā Ā ā BeĀ²āŗ Ā + Ā 2Brā» Ā i = 3
AlBrā ā Ā AlĀ³āŗ Ā + 3Brā» Ā i = 4
Mgā(POā)ā Ā ā Ā 3MgĀ²āŗ Ā + Ā 2POāā»Ā³ Ā Ā i = 5
KBr ā Ā Kāŗ Ā + Ā Brā» Ā i = 2
Solution of Mgā(POā)ā will have the lowest temperature of freezing and the solution of KBr, the highest (always lower, than 0Ā°).
