Sciencemadness Discussion Board

1N koh preparation

reidy2015 - 21-3-2015 at 22:09

How to prepare 1N KOH need help please to understand how to do this .

[Edited on 15-03-2015 by reidy2015]

[Edited on 15-03-2015 by reidy2015]

morganbw - 22-3-2015 at 04:34

Find its molar mass. Add this in grams to enough H2O to make 1 liter of solution. This is the simple answer.
You can use a small amount of math to make whatever quantity you need.
This answer is based on pure KOH.
This is also a 1M solution but be aware that 1M solutions are not always equal to a 1N solution.



[Edited on 22-3-2015 by morganbw]

gdflp - 22-3-2015 at 05:45

How accurate does the concentration need to be? If it just needs to be approximately 1N, then the above answer is correct, however almost all KOH contains at least 10% due to it's extreme hygroscopicity, though some contains significantly more. If you need it to be reasonably accurate, then you should make up a solution accounting for the fact that every 10g of solid only contains up to 9g of KOH, then titrate the solution with a known concentration of acid to find the actual concentration.

morganbw - 22-3-2015 at 05:56

Quote: Originally posted by gdflp  
How accurate does the concentration need to be? If it just needs to be approximately 1N, then the above answer is correct, however almost all KOH contains at least 10% due to it's extreme hygroscopicity, though some contains significantly more. If you need it to be reasonably accurate, then you should make up a solution accounting for the fact that every 10g of solid only contains up to 9g of KOH, then titrate the solution with a known concentration of acid to find the actual concentration.


Agree in total.
That is why I stated my answer as based on pure KOH.

Molecular Manipulations - 22-3-2015 at 07:50

Pure potassium hydroxide can be had by fusing tech. grade KOH in a nickel crucible at over 300 degrees C.

morganbw - 22-3-2015 at 08:19

Quote: Originally posted by Molecular Manipulations  
Pure potassium hydroxide can be had by fusing tech. grade KOH in a nickel crucible at over 300 degrees C.


This takes care of the Potassium carbonate as well?

Molecular Manipulations - 22-3-2015 at 10:48

Nope, carbonate doesn't decompose at standard pressure. It boils at around 1600 degrees C decomposing into potassium and oxide ions and carbon dioxide, which reform carbonate on cooling. There's nothing you can really do about carbonate once you've got it.

reidy2015 - 22-3-2015 at 15:13

Thanks :cool:

Hawkguy - 22-3-2015 at 19:52

Can't you spray Nitrogen or Argon to purge the Carbon Dioxide?