Australia's Science Forum

Hi everyone
How long do you keep your sodium Hydroxide stock bottles for?
Do you also keep them in a dark glass bottle
Reason for asking is Head teacher has said to throw anything older than 3 mths out and I have done a google search where I found out sodium hydroxide should be stored in a plastic bottle not in glass.

I keep mine for longer then 3 months...although it does not hold its molarity long. If I need standardised naoh I re standardise if it is only than a month or so. Mine is stored in whatever I have on hand.

Molten NaOH will dissolve glass so I suppose in soution it may have some effect but I have never heard of not storing it in glass.

I've only heard of not storing it in glass with a glass stopper - but who has those these days?

Its is ONLY the solid form that must be in a plastic bottle NOT GLASS Soultions can go into glass with out a glass stopper.

What are you using it for? I would make up fresh solutions for senior titrations, etc, but for juniors to play with, I keep it until it is all used up! (I have a stack of 250mL reagent bottles) After a year or so, it might precipitate out "gunk" and turn the inside of the reagent bottle translucent, but if still turns litmus blue and will neutralise HCl.

When the stock bottle is empty, I swish it well with 1M HCl and rinse it well and the milky glass reagent bottle will be as good as new!

Same as Ian. Fresh solutions for the senior chemistry and use up the leftovers and old stock for the junior classes. If the sodium hydroxide precipitates in the bottom of the bottle I decant what I can and neutralise the rest before sending it down the drain. My stock of NaOH is stored in glass bottles with plastic stoppers. (If you use glass stoppers you can't get them out. They freeze up.) I don't use these bottles for any other solutions. I use glass stoppers for my 250 and 500ml acid bottles. Yes I have very old bottles which still have glass stoppers but I am gradually adding new bottles with plastic stoppers.