Hoffman voltameter

[elaruu]

Hi,

We are having trouble with our glass Hoffman voltameter leaking. It leaks the sodium sulfate solution from the taps at the top, but only slightly, and the gas escapes very quickly as the pressure builds up. Is there anything I can do to stop the leaking?

It's like this one I think:
https://www.teaching.com.au/product/hof ... electrodes

If we were to buy a new one, is this one good?

https://www.westlab.com.au/hofmann-volt ... glass-type

Thanks.

[Merilyn1]

Have you checked the bungs? As the rubber ages it shrinks and doesn't form a good seal. I could be wrong, but I think you can buy replacement electrodes for the IEC made voltameter. I usually find anything from IEC to be quite durable and often repairable.

[elaruu]

Thanks. The liquid is leaking out of the glass taps at the top. The bungs seem to be OK.

[bigmack]

We had one similar to that at old school . The taps are the taper type like used in burettes . You should be able to pull them apart and reassemble with a slight smear of silicon grease on the taper . just don't use too much grease as you can plug the hole .

Curious you use Sodium sulfate , most labbies use H2SO4 1-2M .

[elaruu]

Thanks bigmack. I will try silicon grease. The teacher specifically asked for sodium sulfate rather than sulfuric acid because she doesn't like the acid leaking everywhere.

[elaruu]

Does anyone have any feedback on the plastic one in the link above?

[labbassistant]

We bought that acrylic one from Haines, I tested it when it arrived and it worked brilliantly! I've always used 0.1m sulfuric acid in the old one but the demonstration video on the Haines website uses 5% nitric acid.
No complaints here!

[PeterK]

I've been using that plastic one for 3-4 years. I use it with 6% sulfuric (it recommends a solution between 5-7% in the instructions). I have had no issues with it and work fine.

[elaruu]

Thanks both. We'll probably get that one too if it's decided we need a new one.