Sulfur dioxide nitrite ions reaction

C. Further warming to 65°C forms white iron sulfate monohydrate [17375-41 -6], FeSO H2O, which is stable to 300°C. Strong beating results in decomposition with loss of sulfur dioxide. Solutions of iron(II) sulfate reduce nitrate and nitrite to nitric oxide, whereupon the highly colored [Fe(H20) (N0)] ion is formed. This reaction is the basis of the brown ring text for the quaUtative deterrnination of nitrate or nitrite. 

The formation of aryl chlorides from arenediazonium ions on reaction with copperfi) chloride is known as the Sandmeyer reaction and also involves the intermediacy of aryl radicals [192]. Copper salts are similarly involved in the reactions of diazonium ions with cyanide, nitrite, and sulfur dioxide. The uses of arenediazonium salts in synthetic reactions forming carbon-carbon, carbon-sulfur, and carbon-boron bonds have been summarized recently [193]. 

Sulfur dioxide or bisulfites are rarely used in combination with nitrites, because their reactions in acidic media yield sulfonates of either hydroxylamine or ammonia, which destroys the preservative activity of the individual additives. The reaction of alkali metal nitrites with bisulfite at lower temperatures leads to the formation of hydroxylamine N, JV-disulfonate, H0N(S03)2, which is hydrolysed to hydroxylamine JV-sulfonate, HONHSOj and further to hydroxylamine (H2NOH). At elevated temperatures complete substitution proceeds with the formation of ammonia JV-trisulfonate, N(S03)j , which is hydrolysed to sulfa-mate, H2NSOj . Subsequent reaction of sulfamate with nitrous acid leads to production of bisulfate ion and nitrogen gas ... 

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