Nitrous Acid, HNO

Parent acid nitrous acid, HNO, nitric acid, HNO, phosphoric acid, H PO. 

Interactions between the geminal bonds have not yet been extensively studied Magnasco developed a method with the bond orbital approach in analyzing interactions [23-27] and showed that the ganinal delocalizations from to and (Schane 6a) significantly depaid on the rotation around ON-OH in nitrous acid (HNO ) 12 [28],... 

Nitric acid, HNO3, and nitrous acid, HNO, form when nitrogen dioxide reacts with water ... 

NITROUS ACID HNO, HYDROGEN NITRITE NaNO, SODIUM NITRITE... 

Nitrous acid, HNO, forms in small ( uantity tf/gether with nitric acid when nitrogen dioxide is dissolved in water.. Nitrite ion can be made together with nitrate ion by solution of nitrogeTi dioxide in alkali ... 

Nitrous acid (HNO ) esters may be formed readily tiom an alcohol and nitrous acid. The usual procedure is to mix sodium nitrite, sulfuric acid, and the alcohol. Organic nitrites are generally very volatile liquids that are only slightly soluble in water but soluble in alcohol. Preparations containing water arc very unstable because of hydrolysis. 

The absorption of the nitrous fumes takes place in such a way that the first absorption tower contains the strongest acid and the last the weakest acid, the practical result being that the first tower not only contains the strongest nitric acid, but also an acid practically free from nitrous acid. The NO passes on from absorption tower to absorption tower, and is oxidised to NO., and absorbed according to the equations given above. Hence the amount of nitrous acid, HNO., increases in each succeeding tower, until in the fifth tower (which is fed with a solution of sodium carbonate) only pure sodium nitrite is formed. 

Nitrous acid—HNO,—47— has not been isolated, although its salts, the nitrites, are well-defined compounds M NO or M (NOj) . 

In many types of S Ar reactions, cationic electrophile formation requires one or more steps after functional group protonation or activation (Fig. 1.2). Alcohols and related functional groups are protonated, and with subsequent cleavage of C—O bond, the carbocation electrophile (11) is formed. In a similar respect, a common method of nitration involves the use of HNOj with H SO. The nitronium ion electrophile (NO, 12) is formed by protonation of nitric acid and subsequent loss of water by cleavage of the N—O bond [8]. The nitrosonium ion electrophile (NO ) may be generated by an analogous transformation from nitrous acid, HNO [9]. Likewise, M-acyhminium ion electrophiles (i.e., 13) may be formed by ionization of A-hydroxymethylamides [10]. 

Nitrous acid (HNO ), a weak electrol3rte (Le., dissociates only partially to produce H ions), may be cited as an example of a weak acid. 

In accordance with the radical mechanism, the reaction in benzene yields trinitrobenzene, p- and w-dinitrobenzenes, 2,4-di- and 2,4,6-trinitrophenol and oxalic acid. The formation of w-dinitrobenzenes, and trinitrobenzene is accounted for by the addition of three and five NO radicals to the primary nitrocyclohexadienyl radical followed by an abstraction of two or three nitrous acid (HNO ) molecules from the adducts. For the trinitrobenzene formation, this process can be represented as follows [4] ... 

Ar—Nj. The diazonium ion results from the reaction of an aniline with nitrous acid (HNO ), prepared by treating sodium nitrite with sulfuric acid. This step is called diazotization. 

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