Which of the following solutes produces a 0.100 molal solution with the lowest freezing point?
MgBr2
O HOCH2CH3
NaNO3
o CGH12O6
Al2(SO4)3
Na3PO4

Al2(SO4)3

Option: E

Explanation:

The freezing point lowering of a solution depends on the number of ions and molecules that dissolve in water solution. So when there are more number of molecules, the freezing point will also be reduced more.

Now let us look at Al2(SO4)3. Here, it produces a total of 5 molecules. i.e (2 Al(3+) and 3 SO4(2-)). If we take the other choices from first:

MgBr2 - It produces a total of 3 molecules. (1 Mg(2+) and 2 Br(-))

HOCH2CH3 - This produces 1 molecule as it remains the same as HOCH2CH3 because it is covalent and does not dissociate in water.

NaNO3 - This produces 2 molecules. (1 Na(1+) and 1 NO3(-))

C6H12O6 - This also produces 1 molecule same as HOCH2CH3 because it is also covalent and does not dissociate in water.

Na3PO4 - This produces a total of 4 molecules. (3 Na(+) and 1 PO4(3-))

Thus, from the above analysis, it shows that Al2(SO4)3 has more molecules compared to others. When there are more molecules, the freezing point is also lower.

a is the correct answer