Sodium carbonate vs sodium bicarbonate

[Rajini]

TL;DR Summary

Identification of sodium carbonate and bicarbonate

Dear all,
How to identify sodium carbonate and sodium bicarbonate? I have these two powders, and did not label.
Thanks for your reply.
Cheers, Rajini

 

[Borek]

They even look differently, but it would be hard to describe. Perhaps dissolve a bit in water and measure pH, the difference should be quite substantial - something below 9 for bicarbonate and around 11 for carbonate.

 

[sophiecentaur]

TL;DR Summary: Identification of sodium carbonate and bicarbonate

Dear all,
How to identify sodium carbonate and sodium bicarbonate? I have these two powders, and did not label.
Thanks for your reply.
Cheers, Rajini

This takes me back more than fifty years. My ex-wife tried sodium carbonate in a recipe for scones. They tasted of soap!! Daft thing was that we tried three times before realising what was our mistake!!!
I bet the taste test would give the answer without adding in the cooking phase.
I don't believe that my suggestion is, in any way, unsafe and I don't suggest a spoonful size sample = just a finger-tip size.

 

[Rajini]

Thanks! I think I need to buy pH paper. Thanks for your suggestions.
Regards,
Rajini.

 

[symbolipoint]

TL;DR Summary: Identification of sodium carbonate and bicarbonate

Dear all,
How to identify sodium carbonate and sodium bicarbonate? I have these two powders, and did not label.
Thanks for your reply.
Cheers, Rajini

Both will fizz if a sample of each is mixed with an acid (using vinegar, maybe). They each will give a different titration curve, so at least if you are in a fitting laboratory situation, you'll find a suggestion of two endpoints for the carbonate, and one endpoint for the bicarbonate. (That is, titrating with an acid titrant.)

 

[hilbert2]

NaHCO$_3$ decomposes and produces carbon dioxide bubbles when heated near the boiling point of water:

https://www.stem.org.uk/system/file...cy_files_migrated/31929-catalyst_24_3_579.pdf

This reaction doesn't happen with sodium carbonate.

 

[chemisttree]

NaHCO$_3$ decomposes and produces carbon dioxide bubbles when heated near the boiling point of water:

https://www.stem.org.uk/system/file...cy_files_migrated/31929-catalyst_24_3_579.pdf

This reaction doesn't happen with sodium carbonate.

Thats right. A little of both in individual test tubes…. heat gently with bunsen burner. The one that seems to “boil” is the bicarb.

 

[sophiecentaur]

Thats right. A little of both in individual test tubes…. heat gently with bunsen burner. The one that seems to “boil” is the bicarb.

To complete the 'School' experiment, the gas that bubbles off could be collected in an inverted tube ('downward displacement of water') and it will extinguish a burning match etc.
An inverted funnel will collect all the bubbles to where you want them.

 

[Vanadium 50]

Just out of curisity, why is it bicarbonate if there is only the one?

 

[symbolipoint]

Just out of curisity, why is it bicarbonate if there is only the one?

He has both materials.

TL;DR SummaryIdentification of sodium carbonate and bicarbonate
Dear all,
How to identify sodium carbonate and sodium bicarbonate? I have these two powders, and did not label.
Thanks for your reply.
Cheers, Rajini

 

[Vanadium 50]

I was unclear. Why is it called bicarbonate, especially since there is only one carbonate?

 

[sophiecentaur]

Just out of curiosity, why is it bicarbonate if there is only the one?

The OP's notation is 'old fashioned' and it's what I learned at School. The Bi, ate, ite, ide etc. parts of the name are a code to tell what's what but it's limited and not intuitive. I was told this by a school lab tech not long ago. There is a new system which is more complicated but describes much more complex compounds. This link has many examples of formulae and common names. It doesn't seem to have any logic to me except for very simple compounds. No doubt the PF Chemists will put name right.

 

[chemisttree]

Bicarbonate because compared to carbonate it appears to have twice the ratio of carbonate to sodium.

Carbonate CO3:Na ratio = 1:2
Bicarbonate CO3:Na ratio = 1:1

Imagine the difficulty of analyzing for that hydrogen in an aqueous solution without modern instruments?

 

[chemisttree]

Same is true of the sodium salt of bisulfite (HSO3)- and sulfite (SO3)-2.

 

[sophiecentaur]

Same is true of the sodium salt of bisulfite (HSO3)- and sulfite (SO3)-2.

The whole process of early Chemistry was pretty arcane and (just as today) very painstaking.
The mass spectrometer is a very handy modern tool and, as it's a piece of Physics, it takes my fancy, compared with bottles and balances.