I want to prepare a solution with equal 45mM Zinc nitrate and Hexamine in Deionized water. After mixing Zinc nitrate and Hexamine in de ionized water I have stirred the solution in a magnetic stirrer about 30 minute at room temperature. After that I found that Zinc nitrate completely dissolved in water but Hexamine didnot completely dissolved in water. It remained as like dust form in the deionized water. How can I make the solution by completely dissolving Hexamine in water? Please help me by providing valuable information.
Solubility of HMTA in water is quite high (about 800g/L) so I recommend stirring longer/more vigorously. You could also try mild heating or sonication to increase the rate of dissolution.
Is it possible that there is an insoluble impurity in the HMTA? How much remains undissolved?
Thank you dear Mr. Aaron Bloomfield. Its analytical grade HMTA. When I only mix HMTA in water it completely dissolved within few seconds. But when I mix Zinc nitrate in that solution then HMTA appeared as dust like and remained ppt in the bottom. Is is due to the appearance of zinc nitrate? Plz help me.
Solubility of Zinc nitrate in water is high (~300g/100ml), so I think the problem is Zinc hydroxide. Solubility product constant of Zn(OH)2 is 3×10-17. It meant solution 45mM zinc nitrate will be precipitated at pH 6 in hydroxide form. So you can use more HMTA, because Zn(OH)2 can dissolve in basic solution, but at this time you get solution of ZnO2- or complex of Zn(OH)2 and amine. Why don't you use the buffer HMTA?
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