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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: stevenjporteous on November 13, 2008, 11:26:37 AM

Title: Crystallization of Caustic solution
Post by: stevenjporteous on November 13, 2008, 11:26:37 AM

Have searched the internet for information about the crystallization of caustic to no avail. Could someone tell me what temperature sodium hydroxide (caustic) at 3.4% strength would crystalize?

Help please...

Title: Re: Crystallization of Caustic solution
Post by: jansenwrasse on November 14, 2008, 08:16:54 PM

Are you refering to its new freezing point?

Title: Re: Crystallization of Caustic solution
Post by: jansenwrasse on November 14, 2008, 09:18:06 PM

I just realized you were not online ::)

 :delta:T_f = (i)(k_b)(m)

so you will need to van't Hoff factor(i) for NaOH ( i = 2)

so ...

:delta:T_f = 2 x 1.86^oC x .85M = 3.162 ^oC

Title: Re: Crystallization of Caustic solution
Post by: jansenwrasse on November 16, 2008, 09:03:32 AM

There is an error in my equation I used the molarity for the calculation and the correct form is molality.  Converty your 2.3% to molality then the rest is correct.  Sorry about that  ::)