Potassiumcyanide
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Sodiumsulfide
Hi
I'm going to try to make Sodiumsulfide by putting (don't know the correct word for putting a gas into a liquid)
Hydrogensulfide into a solution of Sodiumcarbonate.
I think, the reaction will happen following this equalation:
Na2CO3+H2S-->Na2S+H2O+CO2
How fast will it be adsorbed?
Is the equalation correct?
will H2CO3 be formed? would this weak acid disturb (can I use this word?) the reaction or is H2S a stronger acid?
would this also work with NaHCO3 ?
thanks
[Bearbeitet am 7-6-2006 von Potassiumcyanide]
[Bearbeitet am 7-6-2006 von Potassiumcyanide]
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12AX7
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Making Na2S in H2O solution is like Na2O in H2O solution, it ain't gonna happen AFAIK.
According to Wikipedia:
H2S = HS− + H+ pKa = 6.89
CO2 + H2O = HCO3- + H+ pKa = 6.36.
Note this is the CO2(g) to HCO3- konstant. Looks like CO2 would rather dissolve and ionize than H2S ionize. You'll have a hard time.
Tim
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Potassiumcyanide
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if I dry the solution I get after the procedure, what will I get?
ADDED:
it is not as making Na2O in water! if you use water instead of Hydrogensulfide, you will neighter get Sodiumhydroxide nor Sodiumoxide!
ADDED: Na2O would react to NaOH but what should Na2S react to? maybe something like NaSH ?? I can't imagine that this exists...
[Bearbeitet am 7-6-2006 von Potassiumcyanide]
[Bearbeitet am 7-6-2006 von Potassiumcyanide]
[Bearbeitet am 7-6-2006 von Potassiumcyanide]
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12AX7
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| Quote: | Originally posted by Potassiumcyanide
ADDED: Na2O would react to NaOH but what should Na2S react to? maybe something like NaSH ?? I can't imagine that this exists...
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Why not? You just said you accept the change to -OH. -SH is the same darn thing, just using an element below oxygen.
Na2S + H2O = NaSH + NaOH
Tim
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garage chemist
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| Quote: |
Making Na2S in H2O solution is like Na2O in H2O solution, it ain't gonna happen AFAIK. |
Then, why is sodium sulfide always sold as the nonahydrate, with 9 mol H2O? Can you tell me that?
However, you're correct that sodium carbonate won't do the job, since carbonic acid is stronger than H2S.
But with NaOH solution, the H2S reacts very vigorously, producing first the sulfide Na2S and then the hydrogensulfide NaHS. Both are well- defined
compounds, and by adding an equimolar amount of NaOH to a solution of NaHS you get Na2S solution from which the nonahydrate crystallizes in big
impressive crystals (like alum) on slow cooling.
Na2S hydrate is an odorless compund- it does not smell like H2S, since the aerial CO2 only makes NaHS and Na2CO3 from it. Only NaHS stinks.
A solution of Na2S absorbs H2S violently (like HCl in water, you have to watch out for suckback! I have done this myself.), until NaHS is formed.
[Edited on 7-6-2006 by garage chemist]
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12AX7
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| Quote: | Originally posted by garage chemist
Then, why is sodium sulfide always sold as the nonahydrate, with 9 mol H2O? Can you tell me that?
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Nope. 
How do you know it isn't in fact NaSH.NaOH.8H2O? (X-ray diffraction, NMR, SEM and Lord knows what other analytical methods for analyzing structure
aren't admissable! )
I was trying to find the pKa of OH- but only found H3O+. I'm sure it controls such things...
Tim
[Edited on 6-7-2006 by 12AX7]
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