Sodium hydroxide - mixing?

[Sim2]

Hopefully an easy question for you all here;

Mixing 100g of sodium hydroxide into 1000ml of water - when all the powder is added, should the mix be clear or cloudy?

Thanks in advance.
Sim2.

 

[OlliJ]

Hopefully an easy question for you all here;

Mixing 100g of sodium hydroxide into 1000ml of water - when all the powder is added, should the mix be clear or cloudy?

Thanks in advance.
Sim2.

That amount of sodium hydroxide can easely be solubilized in 1000 ml water, the result will be a clear solution. Most likely your NaOH is small pellets, not powder. When mixing the solution warms up quite a bit, be careful.

 

[Sim2]

Yep, I thought/expected it should be a clear solution - guess what, mine's not! It's rather cloudy with an amount that "settles" in the bottle. I added the powder/pellets slowly & yes, it did heat up but had the bottle in a tempering bath of cool water - could this have affected the mix? Been over a day since mixing & still cloudy.

 

[OlliJ]

Are you sure it's sodium hydroxide that you have? The pellets are like tiny buttons.

 

[Sim2]

lol, I hope so! Not like tiny buttons at all. I would describe it as a granular powder - not fine like flour but not as granular as sugar, not a brilliant description but... First time mixing, so expectations were nil! I used the solution in a sepia tone set-up and seemed to work i.e. got the colour change but residue on the prints. ftw the chems were supplied by silverprint inlondon, so should be correct. Any further thoughts? Thanks for assistance so far!

 

[dmb]

Is this tap water? I recall Wiltshire water is very hard - that is has Calcium and Magnesium ions in it. Adding NaOH will precipitate the Calcium and Magnesium as the insoluble hydroxides - Milk of magnesia is magnesium hydroxide - calcium hydroxide is slaked lime - both turn water milky. You could try filtering it but the hydroxide particles are really small.

 

[Sim2]

Yep, it was using tap water, filtered for particles but not for element extraction. Thanks for the thoughts. Guess I will try to filter the "cloudyness". Shame I didn't have any left over that I could mix with distilled water or another alternative, just to see the difference. Ho hum, next time perhaps.
Ain't chemistry fun

 

[paul_c5x4]

Shame I didn't have any left over that I could mix with distilled water

Save yourself some money and get a tub of sodium hydroxide from Boots or a traditional hardware store - You'll probably need to ask for Caustic Soda...

 

[Sim2]

*big grin* off to Boots tomorrow! Thanks for the suggestions.

 

[chiller]

Just check on the container for the weight for volume as some times the hardware store versions are packed with fillers. I purchased one tub that was only 48% [didn't look] and was not successful in the formula I was mixing.

 

[walbergb]

Dido on the hardware store as a source of sodium hydroxide. Ask for lye crystals. The listed ingredient will be...you guessed it, sodium hydroxide.

Definitely use distilled or filtered water to mix both your thiourea and sodium hydroxide. When I first started working with sepia toners, my results were all failures. Nobody could understand why or suggest a solution until someone mentioned using filtered water instead of tap water. It worked for me, so now I mix all my chemicals using filtered water.

 

[richard ide]

It is not a Lye. Caustic Soda is Sodium Hydroxide.



And then again it is.

 

[pdeeh]

Lye seems to be a common US usage for Sodium Hydroxide/Caustic soda; lye as a description or name is used less commonly these days in the UK.

The bottle of Boots Caustic soda I have (& use for photographic purposes) is marked 98% w/w. it doesn't say what the other 2% is unfortunately.

Depending on where you are in Wilts, Sim2, I may be on the same water supply as you, and using plain tap water to mix some chemicals (Sodium hydroxide and Sodium sulfite in particular) does seem to throw a precipitate.

If I use boiled filtered water, I get a better result; or boiled filtered water with a small amount of Sodium hexametaphosphate, or deionised water, no precipitate at all.

I 've found it difficult to obtain large quantities of distilled or deionised water at a sensible price locally, but again as you are in Wilts you may have a Robert Dyas nearby and they usually have deionised water at £6.50/10 litres.

 

[chiller]

If you have a brewery close by they "may" use RO water. They may even sell you some before they turn it into beer.

 

[jochen]

if you say "filtered water", I think you mean deionized water and not only machanically filtered. The rest of the 98 % NaOH are water and sodiumcarbonate from absorbed moisture and carbondioxide from the air. Keep the container well closed. Please wear safety goggles when working with NaOH. If you get it into the eyes, it will cause very severe injuries. In this case you have only a few seconds time to rinse the eyes intensively with water immediately.

 

[dmb]

For my Parodinal (headache tablet, drain cleaner and wine bottle steriliser) developer I use B&Q caustic soda (1kg is £4.98) - I'm lucky with my tap water as is low in dissolved ions even after travelling from Wales in an open canal but I still use it boiled and cooled, which removes a few more ions and also dissolved oxygen and chlorine. Ion exchange water filter jugs can also help reduce total Ca and Mg ions but do increase Na ions but that is not really a problem as most photo chemistry in UK is based on sodium salts. You sometimes do get a little finely divided carbon in the first few jugs of a new filter from the charcoal layer they use to remove chlorine.

 

[Mike Wilde]

Sodium Hydroxide is hygroscopic and reactive as hell. Flakes form of it means that the outside likley is now sodium carbonate.
The OH ion in the hydroxide has ripped the H from carbon dioxide in the air to end up with a water molecule and sodium carbonate as the outcome.

Dissolving sodium carbonate usually takes a fair bit of stirring in hot water. So you are probably seeing undisolved carbonate.

 

[Sim2]

Wow, lots of advice/thoughts here - didn't think that mixing a sepia "additive" would be so enlightening! Somehow wish my chemistry classes form schooldays were more than just fun uses of phosphorus!
Yep, I currently filter for particles/grit and not for extraction of particulars e.g. chlorine so interesting to hear what might be reacting in the tap water. Going to try with de-ionised water or failing that a bottled drinking water but those are said to be full of "helpful" ingredients, which might not be useful for me, ho hum.
One thought, if what I am seeing is sodium carbonate (post #17) would placing my container in a warm water bath & stirring be a way of redissolving it?
btw, the sepia chems worked a treat, just got a cloudy bottle of sodium hydroxide and prints that need a bit more washing due to the residue (like patchy talcum powder - bad description).
Anyway, cheers for the assistance.

 

[Gerald C Koch]

Sodium hydroxide readily absorbs carbon dioxide from the air. The resulting sodium carbonate can precipitate calcium carbonate from tap water causing a cloudy solution.

 

[Sim2]

Ok, so my next question will be - with all these varieties that can be coming from the sodium hydroxide, can they be removed from the "solution" via any other means than a very fine physical filtration?

 

[Fanshaw]

In the UK Wilkinson's sell caustic soda drain cleaner cheaply. I have used it successfully to make pararodinal.

 

[Gerald C Koch]

Ok, so my next question will be - with all these varieties that can be coming from the sodium hydroxide, can they be removed from the "solution" via any other means than a very fine physical filtration?

If you use filter paper, the finer the grade the longer it takes to pass the liquid. It would therefore take a very long time. A filter funnel which has a long stem is useful. But in a practical sense the answer is no. You can allow the solution to sit for a few days and see if the precipitate settles out.

When using sodium hydroxide or sodium carbonate it is best to used distilled/de-ionized water.

Concerning the use of lye specifically intended for drain cleaning AVOID those brands that contain aluminum turnings. The aluminum is added to cause a churning action in the drain as it generates hydrogen gas.

 

[Sim2]

Thanks for all your replies - most informative, great place this.

So, fresh bottle of caustic soda supplied by Boots, fresh bottle of de-ionized water from the petrol station, an initial test using 200ml of water & 20g of caustic soda - dissolved to a clear solution - ta da!
This will be no surprise to you all, but for me, was really good to see & thanks to you guys, I have a small appreciation of why it went differently first time round.
*Good start to the weekend*

Sim2.