Dear all,
As per the literature NH4Cl when dissolved in water, its pH needs to be increased beyond 8.5 and preferably 10.5 (by addition of CaO) so that NH4+ is converted to NH3 and evolution occurs.
My questions to you all is if I dissolve NH4Cl in water (to say 1000 ppm concentration) and heat this solution to 70-80 C, does heating also promote some losses of NH3?
I don't think so. Ammonium chloride solution is slightly acidic ~ 5-6. To evolve ammonia, a base needs to be added. Simply heating in water will not lead to ammonia evolution. I haven't experienced any liberation of NH3 in such conditions.
Ammonium chloride is an inorganic compoundwith the formula NH4Cl and a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. Sal ammoniac is a name of the natural, mineralogical form of ammonium chloride. Ammonium Chloride is comprised of Ammonium NH4 (+1) and Chloride Cl (-1). When compound is placed into water it dissociate just like any other compound.
When ammonium chloride salt is dissolved in water, the solution temperature reduces as heat is absorbed by the reaction that takes place. Hence, the reaction is an endothermic one. The pH of a solution formed this way is below 7 -- that is, the solution is acidic.
Ammonium chloride and water react to yield ammonium hydroxide and hydrochloric acid. Ammonium chloride is called an acid salt, as it is the combination of strong acid and a weak base. The hydrolysis of an acidic salt, such as ammonia
Ammonium chloride in water is acidic and it produces ammonia, H+ ions, Cl- ions and H2O.
The equation goes as this:
NH4Cl +H2O === NH3 + H+ + Cl- + H2O
Total equation being:
NH4+ + Cl- + H2O === NH3 + H+ + Cl- + H2O
the Cl- and the H2O cross out, though the H2O on the product side is actually a combination of the proton that the NH4+ gave off and the OH- from the water on the reactant side so for the net ionic equation the H2O on the reactant side can either be included or not.
Net Ionic:
NH4+ === NH3 + H+
Thankyou Mohit ji, Prem Baboo ji and Mushtaq Ahmad ji for your valuable answers and clarifications
i) The pH of not too concentrate pure ammonia (NH4OH) aq. sol. can be predicted as I have shown elsewhere at this forum:
https://www.researchgate.net/post/How_can_i_calculate_PH_of_an_ammunia_solution_without_using_a_PH_meter
ii) The pH of pure ammonium chloride (NH4Cl) aq. sol. can be predicted as I have shown at:
https://www.researchgate.net/post/What-exactly-does-adjusting-8mM-Ammonium-Chloride-to-solutions-of-pH-of-9-and-10-mean/1
iii) The pH of not too concentrate ammonia / ammonium chloride (NH4OH / NH4Cl) aq. sol. can be predicted as I have shown elsewhere at this forum:
https://www.researchgate.net/post/Can-anyone-suggest-a-protocol-to-prepare-a-buffer-of-NH3-NH4Cl-with-pH-10
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