To what extend can NaOH turn into NaCO3?

[pippo]

People, (oops, I meant to add a "2" after the Na in title)

 

Say one has a 50lb bag of sodium hydroxide pellets, saved for 5 years. Then, say it turns into a solid rock. Then , say one smashed the rock into bits and dissolved the whole mass. In your opinions, how much of the NaOH would have absorbed carbonates from the atmosphere ? When that happens, is it part of the NaOH converting to carbonates, or is it the NaOH is still there and just that the carbonates are adhering/adsorbing onto the NaOH pellet's surface?

 

Thanks!

Oh- if it "converts", is it likely that the entire NaOH can convert over to be fully Na2CO3?

Edited January 26, 2013 by pippo

[Enthalpy]

NaOH stored in the atmosphere for 5 years? Very much of it has reacted, I'd say.

 

From previous observation, NaOH first absorbs air moisture - at least in temperate climate - to form a paste. If your thing is dry and hard now, it could well be that absolutely all NaOH is converted into Na₂CO₃ or NaHCO₃.

 

Smash some and try to dissolve: Na₂CO₃ doesn't, NaHCO₃ and (mind the heat) NaOH do. Use pH paper, cheap and available, to see if it's still any alkaline.

 

But if you know the initial weight, you could just compare.

[John Cuthber]

My guess, and it's no more than a guess, is that there will still be some NaOH in the middle.

I don't know how Enthalpy thinks Na2CO3 doesn't dissolve: it does.

 

(Edited- typo- my bad)

Edited February 7, 2013 by John Cuthber

[Enthalpy]

I mistook it for CaCO₃. My bad, sorry.

[pippo]

sorry for late reply, people, but yeah, turned out MOST of the NaOH was still "there". I titrated BOTH the carbonate and the hydroxide, and the carbonate was minimal. Looks like most of the NaOH was "preserved". Big Thanks for the help.