Which will have the lowest boiling point?

a.

pure water

b.

0.5 m nacl (aq)

c.

1.0 m nacl (aq)

d.

2.0 m nacl (aq)

A.   pure water

Explanation:

= change in boiling point

i = Van'T Hoff factor  

= freezing point constant

m = molality

1. For pure water

, i= 1 as it is a non electrolyte and does not dissociate.

2. For

, i= 2 , as it is a electrolyte and dissociate to give 2 ions and concentration will be (0.5+0.5)=1M[/tex]

3. For

, i= 2 , as it is a electrolyte and dissociate to give 2 ions and concentration will be (1+1)=2M[/tex]

4. For

, i= 2 , as it is a electrolyte and dissociate to give 2 ions and concentration will be (2+2)=4M[/tex]

Thus as vant hoff factor is lowest for pure water and thus the boiling point will be lowest.

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