ScienceHideout
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Stock Solutions-
I just ordered 30+ bottles all longing for stock solutions to be made and put in them. Some of them I have an idea of what to put in them (the stuff I
am constantly stirring in to water- like CuSO4 and such). But I don't know what other solutions I should make. I have 100+ chemicals, and only 30+
bottles, so it should be difficult- I wanna make a solution of everything! lol
So anyways- I want to know what all of your stock solutions that you most commonly use are.
I am always sure to keep 3M NH4OH and 1M NaOH nearby.
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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Lithium
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a concentrated solution of ammonia in dry ethanol or methanol is handy for anhydrous ammonium salt preparation, IMO
Li
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chemrox
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NaHSO3 is handy to have. 1N, 2N & 6N HCl same series with NaOH. 20% acetic acid is good to have. Brine is good to have at least a L of if
you're doing organic syntheses. Infusions of Caffea arabica are best prepared as needed, like every afternoon. 40% EtOH obtained from barely beer
through copper pot and coil may save the day.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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woelen
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I hardly have any stock solutions. I once did, but I stopped with this, because quite a few stock solutions quickly deteriorate much faster than the
solid chemicals.
I have had sulfite solutions being oxidized to sulfate, I had mould in solutions of glycerol and citrates, my solution of copper sulfate formed a very
fine precipitate, due to hydrolysis of copper(II) ions and a similar problem I had with solutions of FeCl3. The pure chemicals kept well, the
solutions deteriorated.
At the moment, the only specially prepared working solutions I have are 20% H2SO4, 10% HCl, 30% HClO4, 20% HNO3 and 10% H2O2. All of these are made
from more concentrated acids and solutions.
So, I switched strategy. I now have small work-bottles in which I store 10 to 20 grams of chemicals and I have larger bottles, which I keep closed
always, except when I need to refill my work-bottles. In this way, my larger quantities of chemicals keep well, because they are kept very well sealed
and only open up every few months or even less frequently. When working with the chemicals I do not have to deal with large heavy bottles, but with
small canisters of 25 ml or so which are a pleasure to handle. Another advantage of this approach is that accidental contamination of my chemicals
only affects the small amount in the work-bottle and not the total amount in the larger bottle. Yet another advantage is that at my work-place in the
lab I only have very small quantities of chemicals. The larger bottles are stored somewhere else. This reduces the risk of having bigger quantities of
chemicals nearby while an experiment gets out of hand.
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jamit
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I agree with Woelen. Beyond just the common stock solution, there is no need to make 30+ solutions unless you plan of using them soon - or unless you
have a lab refrigerator to keep the solution fresh.
It's better just to have some very common stock solution (like naoh, hcl, h2so4, hno3, etc.) and the rest should be made on the fly on a need basis.
I also have several other stock solutions like BaCl2 (for sulfate test), KI (for lead test), and a few others which i can't remember. Luckily, I have
a refrigerator dedicated to keeping my chemicals cool and fresh.
Anyway, I hope these suggestions help. Good luck.
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Endimion17
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I've got few basic ones like copper sulphate, sodium hydroxide, hydrochloric and sulphuric acid, sodium hydrogencarbonate for washing and neutralising
organic stuff... I agree with woelen, they deteriorate and if you want to do anything analytical, it's best to prepare them each time. The ones I've
got are for quick microscale identifications, nothing fancy.
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99chemicals
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One that is nice to have is sodium thiosulfate. If you are dealing with any of the hallogens it can neutralize them.
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ScienceHideout
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I've never had any problems with my copper sulphate- because I got some fine advice from a friend to add a couple drops of H2SO4. It stabilizes it to
prevent hydrolysis.
Anyways- thanks for all the imput!
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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Hexavalent
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What a great way to potentially ruin a good qualitative/quantitative analysis...the best solution is, as others mention, just to make it up as you
need it.
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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Swede
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3M KCl for pH probes... Conc. KOH/NaOH... Sodium bicarb. Silver nitrate. One or two others, but not much at all, and only those that don't
deteriorate.
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