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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Computerized on August 23, 2009, 07:08:17 PM

Title: Which has the lowest freezing point?
Post by: Computerized on August 23, 2009, 07:08:17 PM

18. Which of the following solutions has the lowest freezing point?

(A) 0.20 m C6H12O6, glucose
(B) 0.20 m NH4Br
(C) 0.20 m ZnSO4
(D) 0.20 m KMnO4
(E) 0.20 m MgCl2 

Title: Re: Which has the lowest freezing point?
Post by: Borek on August 24, 2009, 02:48:34 AM

Please read forum rules (http://www.chemicalforums.com/index.php?topic=33740.0).

Title: Re: Which has the lowest freezing point?
Post by: Computerized on August 24, 2009, 09:28:36 PM

Well, I thought it was E because it dissolves into 3 ions, whereas all the others dissolve into 2 or less. Am I correct?

Title: Re: Which has the lowest freezing point?
Post by: MrTeo on August 25, 2009, 01:24:37 AM

Right, in fact when you work with the same kind of solutions (same solvent, so same K_cr and same molality) the only thing that varies the final value is the number of ions got from dissociation ((https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fwww.forkosh.dreamhost.com%2Fmimetex.cgi%3F%7B+%5Calpha+%7D&hash=535a401cbf847b557f85d3923f548dc9e276f6e0))

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fwww.forkosh.dreamhost.com%2Fmimetex.cgi%3F%7B+%5CDelta+t%3DK_%7Bcr%7D+%5Ccdot+m+%5Ccdot+%5Cleft%28+%7B1+%2B+%5Calpha+%7D+%5Cright%29+%7D&hash=fa79586dab198302c6e8e50c32bfa76832aee523)