Hi,
We accidentally bought Nessler's Reagent A (potassium tetraiodomercurate(II) solution) instead of Nessler's Reagent (for detection of ammonia).
I understand that we can add NaOH at a certain ratio to this Reagent A, in order to produce the complete Nessler's Reagent. But I don't know how much to add.
Would appreciate any help!
Please check : Nessler’s Reagent: Definition, Formula, and Uses (chemistrylearner.com)
Preparation of Nessler’s Reagent
Nessler’s reagent is prepared by mixing 2 g potassium iodide in 5 ml water. To this solution, 3 g of mercury (II) iodide is added, and the resulting solution is made to 20 ml. Finally, 40 g potassium hydroxide (30 %) is added to provide the alkaline base [1].
Application of Nessler’s Reagent
Nessler’s reagent is used to detect ammonia. The solution becomes deep yellow in the presence of ammonia until a brown precipitate is formed [2].
📷Nessler’s Reagent Reaction
References
Johan De meester thank you, I'm well familiar with the original reciepie- I just don't know how it relates to Nessler Reagent A (which contain Potassium mercury(II) iodide solution). I bought it as a bottle of 500ml. Should I take 20ml of it, and add 40 g potassium hydroxide (30 %)?
I have the same doubt. The same thing happened to me as to you Barak Dror. I bought Merck's reagent A, and I don't know how much sodium hydroxide to add. I found that NaOH is added at 25% w/v, however, I don't know if you add it already diluted, or if you prepare solid NaOH with the volume of the reagent. If you were able to solve your doubt, I would appreciate if you could comment it.
Regards!
Barak and Nicolas, it is pretty easy, the solution you have bought is neutral in pH then you still need to add alkali - if the solution you have at hand is alkaline, then you have the Nessler reagent at hand, not ?
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