i am trying to make 3KCl solution for storage buffer of ph meter.
but the powder of KCl doesn't solve in water, i tried to stir it on hot water and do autoclave to increase high pressure and temperature. but i failed. it. it looks suspension
do you have a solution?
Potassium chloride should be soluble in water at 20C to over 300g per litre. Are you sure you have the right material?
Potassium chloride should be soluble in water at 20C to over 300g per litre. Are you sure you have the right material?
Oki,
did you put the whole amount (11.1825g KCl) into the 50ml A.dest at once or peux a peux??
Really slow dissociation of huge amounts (IMHO) (despite not at the saturation point proper) sometimes will result in incomplete dissolution. Add always only small amounts and let dissolve completely, then add the next small amount....and so on...
Best wishes and regards, Wolfgang
Oki, I am sorry. No other solution.
For “educational” and “academic” reasons I did this task by myself right now:
- Mixing with a magnetic stirrer at “middle” speed.
- Up to about 16-18g KCl (crystalline) dissolved more/less rapidly and completely but the rest of some 0.5 - 1 g (or even less) left a small amount of undissolved grains in the forming solution. After 5 min. further mixing:
- Changing the content (=70+ ml KCl-solution already) by decantation out of the Erlenmeyer flask, filling the contents into a 100 ml graduated measuring cylinder, dissolving the remaining grains in the Erlenmeyer flask three times (and each time decanting afterwards) with a volume of approx. 10, 8 and 8 ml A. bidest. each step (because this was the necessary total amount of A. dest. to fill up to an exact end volume of 100 ml [= 3M KCl]).
- There was NO VISIBLE preciptate/grains left in solution.
I don’t know why you were / are not able to get total dissolution of your stuff, whatever this might be.
I used 100% clean glassware and 100% clean, fresh A. bidest. at room temperature (i.e. no heat was applied).
It seems to me that at 70+ ml solution the dissolution was near,or at the saturation point already.
I am really sorry that you have to look either for a new charge/lot of KCl, try to clean thoroughly your glassware (usually rinsing in acidic water – acetic acid, hydrochloric acid or chromosulphuric acid, if available [since nowadays banned chemical solution], and/or else and check perhaps also your (deionized) water / A. bidest or whatever you used.
Best of luck,
Wolfgang
thank you for your advice.um,, i tried on following your step. but it doesn't work. i think the problem is water. i used second distilled water. to my mind, the machine is so bad that it couldn't filt mineral on water, i have to try on another water. otherwise i am gonna try to change the powder from another company.
The solubility of KCL is 32-34 gm/mL in any type of water at 20-40 degree celsius. suppose if you are making 100 mL of 3M KCL solution simply add required KCL powder in at least 85mL of water, and mix it for 1-2 hour.
I have made 5M KCl in double distilled water. I measured the exact amount to be added in 100 ml DD water. Then on stirring, I added KCl slowly slowly in to water. The last 1 gram took the most time when I had to leave it on stirring for 3-4 hours.
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