flashpoint
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Sodium Hydrogen Carbonate vs. Sodium Bicarb
I work in a pool store and just had a lady question the differences between Sodium Hydrogen Carbonate, and Sodium Bicarbonate. My understanding is
that they are both Buffers of Alkalinity...although Bicarb does raise the pH...but Sodium Hydrogen Carbonate does not?
Can anyone explain this to me?
All I got in this world, is my balls and my word.
And I don\'t break em\' for nobody!
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16MillionEyes
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Well, if I understand you well then this is your question:
"NaHCO3 = NaHCO3?"
[Edited on 25-7-2007 by __________]
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kaviaari
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I think you meant sodium bisulfate and sodium hydrogen carbonate (or bicarbonate). Then it would make a lot more sense. When bisulfate dissolves it
leaves the solution acidic and the bicarbonate makes it basic.
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Xenoid
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Most pool stores around here sell sodium carbonate (soda ash) for raising pH.
Sodium bicarbonate = sodium hydrogen carbonate = baking soda.
Sodium bicarbonate decomposes at 100oC to sodium carbonate + water + carbon dioxide. Hence its use in baking, as a raising agent in cakes etc.
Xenoid
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cbfull
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Xenoid is correct.
Another way of looking at it is to consider CO2 dissolved in water, which forms carbonic acid. This is essentially a carbonyl (C=O) with an acidic OH
on both sides of the carbon. Add an equimolar amount of NaOH and essentially one of those OH's becomes O- Na+, the other OH remains intact. This is
sodium bicarbonate, a relatively weak base.
Add another equimolar amount of NaOH and both acidic hydrogens will become Na+, and this is sodium carbonate. Sodium Carbonate (Na2CO3) is a stronger
base than bicarbonate.
Strengths as a base in solution follows this trend:
NaOH > Na2CO3 > NaHCO3
Hope that is relevant and makes sense.
Bicarbonate tends to be a confusing ion because the H fools people into thinking it should dissociate in water making an acid.
[Edited on 8/2/2007 by cbfull]
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not_important
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| Quote: | Originally posted by cbfull...
Add another equimolar amount of NaOH and both acidic hydrogens will become Na+, and this is sodium carbonate. Sodium Carbonate (Na2CO3) is a stronger
base than bicarbonate.
Strengths as a base in solution follows this trend:
NaOH > NaHCO3 > Na2CO3
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You've contradicted yourself there.
NaOH > Na2CO3 > NaHCO3
is what you meant to type, and is what you said just above that.
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cbfull
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I sure did, thanks for catching that! I'll correct it just to avoid confusion.
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