Author Topic: Using sodium bi-carbonate directly  (Read 1355 times)

Offline kephra

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Using sodium bi-carbonate directly
« on: May 18, 2018, 05:16:44 PM »
Why do we bother to bake the baking soda?

Baking soda = NaHCO3 (sodium bi-carbonate)
When heated, it turns into:
Washing soda = Na2CO3 (sodium carbonate) plus water and carbon dioxide.

So, washing soda has twice as much sodium per molecule.

That means that we would have to use twice as much to obtain the same result.
However we cannot make a 2 Molar solution of baking soda.  That exceeds its solubility.

Baking soda is made by bubbling carbon dioxide gas through a saturated solution of washing soda.  The sodium bi-carbonate is less soluble, so it precipitates out.

So we could use 2ml of 1 Molar baking soda per liter to get the same results.

Try it out.

To make 1 Molar sodium bi-carbonate solution, use 8.4 grams in enough distilled water to make 100ml.
You might have to warm it up to get all the powder to dissolve.
« Last Edit: May 18, 2018, 06:30:57 PM by kephra »
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Offline Neofizz

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Re: Using sodium bi-carbonate directly
« Reply #1 on: May 18, 2018, 10:31:14 PM »
To make 1 Molar sodium bi-carbonate solution, use 8.4 grams in enough distilled water to make 100ml.
You might have to warm it up to get all the powder to dissolve.

And here we are where science gets 'funny' again.

Wikipedia says it's solubility in water at 20C is 9.6 grams per 100 mls.

Meanwhile, at the Sciencing website they say you can't dissolve more than 7.8 grams into 100 mls.
https://sciencing.com/dissolve-sodium-bicarbonate-7804558.html

Hmm (scratching head).  :o
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Offline kephra

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Re: Using sodium bi-carbonate directly
« Reply #2 on: May 18, 2018, 11:09:57 PM »
Maybe we should ask snopes  :o  They know everything.
« Last Edit: May 19, 2018, 01:39:31 AM by kephra »
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Offline Bobby

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Re: Using sodium bi-carbonate directly
« Reply #3 on: May 19, 2018, 09:33:22 PM »
 
Quote
And here we are where science gets 'funny' again.

Wikipedia says it's solubility in water at 20C is 9.6 grams per 100 mls.

Meanwhile, at the Sciencing website they say you can't dissolve more than 7.8 grams into 100 mls.
https://sciencing.com/dissolve-sodium-bicarbonate-7804558.html

Hmm (scratching head).  :o

 
So the way we mix it in “enough distilled water to make 100ml total” for our electrolyte, it would take even less! 

  Would the elevation at where it is being mixed make a difference?

Bobby
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Offline kephra

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Re: Using sodium bi-carbonate directly
« Reply #4 on: May 19, 2018, 09:42:32 PM »
Quote
  Would the elevation at where it is being mixed make a difference?
No, solubility does not depend on air pressure or altitude.
BTW, mine dissolved, but left a very fine layer on the bottom of my bottle which I think is some anti-caking agent.  I used generic store brand baking soda.
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Offline cfnisbet

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Re: Using sodium bi-carbonate directly
« Reply #5 on: May 20, 2018, 08:54:36 AM »
Now, the next interesting thing about this (for me) is the resultant pH of the distilled water after the electrolyte has been added to the distilled water ready for the electrolysis to start.

I will explain shortly.

john72

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Re: Using sodium bi-carbonate directly
« Reply #6 on: April 18, 2021, 08:55:55 PM »
Can boraks be used as an electrolyte? formula : Na₂[B₄O₅(OH)₄]·8H₂O