Making up Sodium Hydroxide solution

[Duffbeer]

All seems a tad risky for little gain, why not just buy some ready made? £1.85 for 114ml may seem pricey but got to be much safer.

[koomber]

Cannot see it stated specifically but add the sodium hydroxide (NaOH) to the water. Never the other way round.

The combination creates heat and when the water gets to the NaOH it can boil and throw a concentrated solution off. If you add the NaOH to the water there is the mass of water that needs to be heated so much less chance of it bubbling. It will still get warm.

We used to make 50% Sodium hydroxide soln at my work. You needed to be VERY careful about the rate of addition. Put it in too quick and it would be very easy to get the water to pretty much boil.

[kirk]

Cannot see it stated specifically but add the sodium hydroxide (NaOH) to the water. Never the other way round.

The combination creates heat and when the water gets to the NaOH it can boil and throw a concentrated solution off. If you add the NaOH to the water there is the mass of water that needs to be heated so much less chance of it bubbling. It will still get warm.

[SiSandrine]

,

thanks, so what was the calculation you used to test your .1N against citric acid?

I can't remember where the 42g / 4.5 litres came from. It definitely worked but most accurate is to measure as tartaric. It will take a better mathematician or chemist than I am to explain. In any case see the following link which I have extracted the key paragraph from here

"Be aware that all the acids - tartaric, malic and citric - will affect the TA values differently. While a one-gram addition of tartaric acid will increase the TA by one gram per litre, malic acid will increase the TA by about 1.12 and citric acid by about 1.17. They also affect the flavour differently. So lab tests are essential. "

http://www.bcawa.ca/winemaking/acidph.htm

Hope this helps

[parabolic]

Yes. If you take a known amount of tartaric acid e.g 5 grams and then make that up to 1 litre with water. You can then use the formula [75 x 0.1 x NaOH (ml)] x Sample (ml) = Acidity (gm per litre) posted by Northern Winer in the thread linked earlier in this thread. I think that should work.

,

thanks, so what was the calculation you used to test your .1N against citric acid?

[SiSandrine]

so sorry for digging up yet again another old thread , but where do you get that information from about the use of citric acid as a standard for standardising NaOH?

I have only found detailed info on standardising with HCI or KHP, the later being the best method.

I'm just very curious as I'm trying to find a way to sort out my 0.1N NaOH but I never have seen away to do it with citric and can't find the detailed information on it.
I have tried the citric acid method above but my result was way off from 6.5ml which I know could be an indication that my 0.1N is not 0.1N, but I would like to see the numbers on how cirtic acid can be used. If citric acid can be used, that must mean surely that Tartaric acid can be?

Yes. If you take a known amount of tartaric acid e.g 5 grams and then make that up to 1 litre with water. You can then use the formula [75 x 0.1 x NaOH (ml)] x Sample (ml) = Acidity (gm per litre) posted by Northern Winer in the thread linked earlier in this thread. I think that should work.

[P cuthbert]

Just a quick reminder here. NaOH (sodium hydroxide, lye) is a very caustic substance.

Keep plenty of water to hand or have access to running water. Also, as suggested above, having a neutralizing agent (citric or acetic acid-5% vinegar) is important.

Wear your protective equipment religiously. Nitrile gloves and face shield or chemical goggles are recommended. A chemical apron is advised, and don't forget your footwear. Closed toed shoes, or better, wellingtons.

Your safety when handling chemicals is of the utmost importance. I regularly handle 23% solution, and when doing so, I am wearing a full chemical suit.

Take care and you will be able to enjoy the fruits of your labours.

[parabolic]

Just thought I'd give a quick update on this as it has been very successful.

So I bought a tub of Boots Caustic Soda (sodium hydroxide) and following (the excellent advice in) this thread I added just over 4 grams to 1 litre (weighed) water.
In order to test this worked I weighed out 4.5kg of water and added 42grams citric acid into that. I mixed / shook well and ensured all dissolved.
I then added 5ml of the citric acid water to a glass jar, 5 drops of phenolpthalein.
Titration showed 6.5ml of my 0.1N NaOH solution needed exactly. So perfect results, I was very pleasantly surprised.
I now have plenty of NaOH solution, a test jar of 42gm/4.5ltr water and high confidence in my titration assembly. Top tip - a jam jar is so much easier than a test tube for titration. It is stable, has a nice wide opening and the wine doesn't squirt out the top if you need to boil the C02 off first.

Thanks for your assistance guys. Next step S02 assembly.

so sorry for digging up yet again another old thread , but where do you get that information from about the use of citric acid as a standard for standardising NaOH?

I have only found detailed info on standardising with HCI or KHP, the later being the best method.

I'm just very curious as I'm trying to find a way to sort out my 0.1N NaOH but I never have seen away to do it with citric and can't find the detailed information on it.
I have tried the citric acid method above but my result was way off from 6.5ml which I know could be an indication that my 0.1N is not 0.1N, but I would like to see the numbers on how cirtic acid can be used. If citric acid can be used, that must mean surely that Tartaric acid can be?

[koomber]

Just thought I'd give a quick update on this as it has been very successful.

So I bought a tub of Boots Caustic Soda (sodium hydroxide) and following (the excellent advice in) this thread I added just over 4 grams to 1 litre (weighed) water.
In order to test this worked I weighed out 4.5kg of water and added 42grams citric acid into that. I mixed / shook well and ensured all dissolved.
I then added 5ml of the citric acid water to a glass jar, 5 drops of phenolpthalein.
Titration showed 6.5ml of my 0.1N NaOH solution needed exactly. So perfect results, I was very pleasantly surprised.
I now have plenty of NaOH solution, a test jar of 42gm/4.5ltr water and high confidence in my titration assembly. Top tip - a jam jar is so much easier than a test tube for titration. It is stable, has a nice wide opening and the wine doesn't squirt out the top if you need to boil the C02 off first.

Thanks for your assistance guys. Next step S02 assembly.

+1 on the Jam Jars. I use an old beer bottle for preference. Easier to grap the top and swirl than using a wide mouthed jam jar.

[SiSandrine]

Just thought I'd give a quick update on this as it has been very successful.

So I bought a tub of Boots Caustic Soda (sodium hydroxide) and following (the excellent advice in) this thread I added just over 4 grams to 1 litre (weighed) water.
In order to test this worked I weighed out 4.5kg of water and added 42grams citric acid into that. I mixed / shook well and ensured all dissolved.
I then added 5ml of the citric acid water to a glass jar, 5 drops of phenolpthalein.
Titration showed 6.5ml of my 0.1N NaOH solution needed exactly. So perfect results, I was very pleasantly surprised.
I now have plenty of NaOH solution, a test jar of 42gm/4.5ltr water and high confidence in my titration assembly. Top tip - a jam jar is so much easier than a test tube for titration. It is stable, has a nice wide opening and the wine doesn't squirt out the top if you need to boil the C02 off first.

Thanks for your assistance guys. Next step S02 assembly.

[SiSandrine]

Just on the test then, do you find with reds it is the point that it starts to turn green/grey or the point after that when the pink colour comes. I have seen both suggested and there can be as much as 1ppt difference.

(As I don't yet have a PH meter).

[koomber]

Thanks for all your advice guys. I intended to prepare the water in a measuring jug (weighed at 1 litre) on my digital scales. I will then add the sodium hydroxide to a ramekin (as the scales have a tare function) and transfer this straight to the water in the measuring jug. The bottle the caustic soda comes in has a narrow neck and is 'pourable'.
What I am going to do with 1 litre of the stuff I don't know as it will have no doubt 'gone off' before I use it all - clean the drains maybe. I like the newspaper / sellotape tip and yes - family will be banned too.

Sounds good. If you don't land exactly bang on the desired concentration you can work out the strength of the caustic solution by:

Weight added/40.79 = normality of sodium hydroxide soln.

Then using the info in northernwiners post here:

http://www.winesathome.co.uk/forum/showthread.php?t=4123&highlight=richie+acid+test+kit

you can work out your concentration in tartaric acid

(PS: The point where the indicator soln starts to turn is roughly pH 8.2)

[SiSandrine]

Thanks for all your advice guys. I intended to prepare the water in a measuring jug (weighed at 1 litre) on my digital scales. I will then add the sodium hydroxide to a ramekin (as the scales have a tare function) and transfer this straight to the water in the measuring jug. The bottle the caustic soda comes in has a narrow neck and is 'pourable'.
What I am going to do with 1 litre of the stuff I don't know as it will have no doubt 'gone off' before I use it all - clean the drains maybe. I like the newspaper / sellotape tip and yes - family will be banned too.

[koomber]

I tend to weigh my water as well (1g/ml for distilled water at 20C). With a set of reasonable digital scales it's certainly as accurate as a volumetric flask for small volumes and one less thing to break.

cheers

Mark

Depends on the chemical and the loading, but broadly speaking your right. For acid calcs in wine any error in weighing/measuring will likely be over shadowed by the assumption that all the acid is tartaric (or sulfuric if you use a ritchies kit).

[koomber]

One thing spending 30 years in an analytical lab does is to make you forget that at the start of those 30 years one had considerable training on how to safely and accurately dispense substances. So perhaps the salient advice should be - If you don't think you can quickly weigh out ca 4g of something WITHOUT spilling any, then DON'T try to do it with caustic soda...

If you (or any of your family) do manage to get some on your skin, it will feel quite 'soapy' - this is the caustic rotting your flesh


Derek

Yup. Caustic is not fun if it goes wrong. I did have fun in a lab once where they were testing cement blocks and part of the procedure involved keeping the blocks submerged in 38°C water. One of the guys couldn't figure out how soap kept getting into the water bath, since if he stuck his finger in it would feel soapy.

Poked a pH probe in the bath and it was about pH 13-14. It wasn't soap in the bath it was the caustic from the cement saponifying the natural oils on his skin