1.

A 0.2 molal aqueous solution of a weak acid HX is 20% ionized. The freezing point of the solution is (k_(f) = 1.86 K kg "mole"^(-1) for water):

Answer»

`-0.45^(@)C`
`-0.90^(@)C`
`-0.31^(@)C`
`-0.53^(@)C`

SOLUTION :HX IONISES in solution
`HXhArrH^(+)+X^(-)`
`alpha=(i-1)/(n-1)or 0.2=(i-1)/(2-1)`
`DeltaT_(f)=ixxK_(f)xxm`
`=1.2 xx(1.86^(@)Cmol^(-1))xx(0.2 m)`
=`0.45^(@)C`
Freezing POINT of solution
`=0^(@)C-45^(@)C=-45^(@)C`.


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