NaOH makes burrette stuck? (1 Viewer)

[Illena]

yeah in most books I found, they said that you can put NaOH in burrette for titration but back here in the Indonesia you can't do that because it will cause the burrette to stuck and the end is getting break.

Does anybody have any suggestion why?

I say it is because the climate here is much damp and NaOH react with that water vapour in the air and cause the property to change
But I'm not convince of the idea and if I'm wrong please tell me, also ur suggestion ^^

 

[Serius]

nice engrish

anyways i dont know how it could make the burrette stuck, i havent really heard of it happening and i dont thing a humid atmosphere would have a significant effect on it[unless indonesia is like living in a sauna, which it isnt]

i say just go with the titration, if it happens it happens, no biggie and its pretty easy to clean out[we used like .01 mol, so i could suck it out if you really wanted and not be hurt, i just wouldnt suggest it]

who yold u it would make the burrette stuck? ask them for a chemical reason[ not just reacts with atmosphere] get them to show u formula or a text stating why

 

[Riviet]

You never know, it might actually be the high humidity/hot weather that causes the NaOH to stick to the inside of the burrette. Maybe you could try the experiment in a well air-conditioned room. That way you don't have to worry about the NaOH getting stuck and do the rest of the titration procedure.

 

[helper]

Same in Australia but now most burettes have a plastic turncock so it isn't as big a problem but still can occur in the end if the burette is not cleaned properly. Same reason why you don't store NaOH in a glass bottle with a glass stopper. It reacts with the glass to form sodium silicate

 

[Illena]

Nope that's what my seniors and my chem teacher told me. last year and the year before last year they do put some NaOH in the burrette in lab times and most of them got the burrette tap got stuck so this year they told me to never put NaOH in burrette anymore

Well in Indonesia you can say it is like a sauna with hot and damp air...

 

[helper]

Did you read what I said.

They stick in Australia as well if they are made of glass or not cleaned properly.

The NaOH reacts with glass to form Sodium Silicate, which fuses glass together. This will fuse Burettes closed or stock bottles lids on.

It is the same in Australia but since the modern stopcocks are not glass it is not as big a problem but still can occur. Standard lab practice has always said do not put NaOH in the burette.

 

[jamesy_1988]

Well I've heard of the of the taps sticking, but it was due to poor maintance, and the taps don't only stick for NaOH. It all depend on how well they are cleaned...so make sure that you clean them well. Also a good idea is if you are putting NaOH in the burette, after you have finished using it, let a 0.1mol solution of HCl or another dilute acid in the burette to nuetralise the NaOH.

Also another reason why you shouldn't put NaOH in the burette is that the NaOH 'eats' away at the inside of the burette, and after repeated uses, it will mke the scale on the burette inaccurate, thus giving incorrrect results.

Jamesy

 

[Illena]

(sorry helper really sorry T_T)

what state is the sodium silicate that is produce? and why it can cause the burrette tap to stuck?

 

[helper]

Its a solid. IT shows up as a white solid, like crushed glass, so it may really be a clear crystal.
It is also the thing doing the etching Jamesy is talking about. However, it will do the same thing over time to any glass, so pipettes over time will also be etched and volume accuracy be lost.

So it comes down to always clean glass well when you have used NaOH in it.

If you want to see it, find an old glass bottle with a glass stopper. Fill with NaOH and leave it. Eventually the stopper will fuse on.