Question

What is the freezing point of a 0.05500 m aqueous solution of `NaNO_3`, if the molal freezing-point-depression constant of water is 1.86°C /m?

Answer 1

We know the depression of freezing point

`DeltaT_f=K_fxxbxxi`

Where

`K_f->"cryoscopic consrant"=1.86^@"C/m"`

`b->"molal concentration"=0.055m`

`i->"Van'tHoff factor"=2" for "NaNO_3 "*"`

`"*"` As `NaNO_3` dissociates as follows producing 2 ions per molecule.

`NaNO_3rightleftharpoonsNa^+ +NO_3^(-)`

So

`DeltaT_f=1.86xx0.055xx2~~0.2`

So the freezing point of the given aqueous solution will be `-0.2^@C`