Potassium carbonate / bicarbonate

[Claude Jolicoeur]

I was looking at Potassium carbonate for acidity reduction, but most
wine supply stores only have the bicarconate... which they also sell
for acidity reduction.

However, from what I can read in Wikipedia, the bicarbonate makes a
weaker base and more of it would be required.

Any opinion or recommandations?

Claude

[Claude Jolicoeur]

I wrote:
> I was looking at Potassium carbonate for acidity reduction, but most
> wine supply stores only have the bicarconate... which they also sell
> for acidity reduction.

It seems this one passed unnoticed...
I would really appreciate to have an opinion on the difference between
Potassium carbonate and Potassium BIcarbonate for acidity reduction!

Thanks
Claude

[Andrew Lea]

I can give you fact, not opinion ;-)

Potassium carbonate (K2CO3) is a stronger base (alkali) than potassium
bicarbonate (KHCO3), because both its potassiums are replaceable with
hydrogen whereas in the bicarbonate one has already been replaced.

You can find equivalent pH values for 0.1N solutions given here
http://www.engineeringtoolbox.com/bases-ph-d_402.html

The difference is exactly parallel to that between sodium carbonate
(washing soda) and sodium bicarbonate (baking soda).

So in terms of acidity reduction you get more bangs per buck from the
carbonate. But it's more dangerous to handle e.g. if you get it in your
eyes (but not as dangerous as the hydroxide). Maybe that's why the
bicarbonate is also sold for wine acidity reduction even though it's
less effective.

Andrew

--
Wittenham Hill Cider Pages
www.cider.org.uk

[Claude Jolicoeur]

Andrew Lea wrote:
> Potassium carbonate (K2CO3) is a stronger base (alkali) than potassium
> bicarbonate (KHCO3), because both its potassiums are replaceable with
> hydrogen whereas in the bicarbonate one has already been replaced.

Exactly the answer I was hoping to get...
Thanks, Andrew
Claude

[Jake Holweger]

My question to you Andrew would be that I am using either potassium bicarbonate or potassium carbonate in an experiment involving radishes. Would you think that I should use potassium bicarbonate for the safety of the plants?

[m...@kulahavenfarms.com]

I’m sure you’ve already answered your question in the past four years but if not, here you are.
I’m not a chemist although I own an aquaponics farm here in Maui and in my hatchery system I add potassium carbonate (K2CO3) to the water to maintain a base (alkaline) environment for
fingerling rainbow trout. This water then passes through a bio filter (which I don’t believe has any effect on the potassium). After the biofilter this water flows through a raised bed where crops take up the nutrients. As far as I can tell the plants arnt affected from the potassium carbonate. Although if fish are exposed to potassium for a extended period a few will start to develop into side swimmers. I use calcium carbonate in the form of crushed coral maintain a perfect ph of 7 in the main aquaponics system (might be of some use to you). I only add a quarter cup of potassium carbonate to a 850 gallon system this seems to increase the ph by .5 possibly closer to 1.

- Max Powell

[AW]

For neutralization of acid I suspect that both carbonate and bicarbonate will behave identically to each other.  

For rxn with 1 mol K2CO3:    2K+ + CO3(2-)  + 2H+ > 2K+ + CO2(g) + H2O

For rxn with 2 mols KHCO3:   2K+ + 2HCO3- + 2H+ > 2K+ + CO2(g) + 2H2O

Its essentially the same chemistry as long as you at low enough pH (<<6.4).  

[Eric Tyira]

College chemistry was many moons ago. 

But if I’m reading this correctly:

1 mol of potassium carbonate will bind 2 free hydrogens to an oxygen, make one water and some carbon dioxide gas. 

2 mols of potassium bicarbonate will bind 2 free hydrogens to oxygen, make 2 waters and carbon dioxide gas. 

They both convert two free hydrogens to water (your acid reduction), but one compound does it with 1 mol and the other does it with 2 mols?

Sounds like the carbonate is more effective than the bicarbonate?

Br,

Eric Tyira

--
--
Visit our website: http://www.ciderworkshop.com
 
You received this message because you are subscribed to the "Cider Workshop" Google Group.
By joining the Cider Workshop, you agree to abide by our principles. Please see http://www.ciderworkshop.com/resources_principles.html
---
You received this message because you are subscribed to the Google Groups "Cider Workshop" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cider-worksho...@googlegroups.com.
To post to this group, send email to cider-w...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Jake Holweger]

This question came from the mind of a 7th grader who barely knew the difference between valence shells and tortoise shells who chose to do a chemistry intensive science competition project. Thank you for the informative responses. While interesting to read, the project was submitted about 4 years ago, and I'm now going into the field of mechanical engineering instead of chemistry like I had originally planned. Best wishes to all of you! Glad that our paths crossed, if ever so briefly.

Thanks,

Jake

You received this message because you are subscribed to a topic in the Google Groups "Cider Workshop" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/cider-workshop/WRLmFtT5lcI/unsubscribe.
To unsubscribe from this group and all its topics, send an email to cider-worksho...@googlegroups.com.