Question

which of the following would result in the lowest freezing point depression(lowering the freezing point of a solution the furthest)?

A) NaCl
B) HNO2
C)Ca(OH)2
D)Na3PO4

the answer is D) but why? I'm just going over test questions I got wrong

Answer 1

look up freezing point depression and the formula will indicate why

Answer 2

I read on it and it looks like the melting point can be depressed by adding a solvent like salt for example.

Answer 3

freezing point not melting point....
http://www.chemistryexplained.com/Ce-Co/Colligative-Properties.html
pay particular attention to i in this formula...that will answer your question

Answer 4

Δ T f = i K f m

where K f is the freezing point depression constant for the solvent (1.86°C·kg/mol for water), m is the number of moles of solute in solution per kilogram of solvent, and i is the number of ions present per formula unit (e.g., i = 2 for NaCl). This formula is approximate, but it works well for low solute concentration

i is the number of ions in the formula. The more ions the lower the freezing point depression?

Answer 5

yes

Answer 6

so do you see why D is the answer?

Answer 7

yes I do thank you surry for pointing me in the right direction.

Answer 8

you are very welcome...colligative properties of solutions can be confusing