Dinitrogen tetroxide, equilibrium with nitrogen dioxide

Nitrogen dioxide forms an equilibrium with dinitrogen tetroxide. When it is cold, the equilibrium favours the second compound. Depending on the thermal conditions, the dangerous reactions will involve one or the other of these two compounds. Their endothermic character makes them hardly stable. 

Nitrogen dioxide rapidly forms an equilibrium mixture with its dimer, dinitrogen tetroxide or nitrogen peroxide [see Eq. (9.11)]. The formation of the tetroxide is favored by low temperature and high pressure104. 

Heat of Reaction and the Tendency of the Reaction to Take Place. It has been pointed out in earlier paragraphs tiiat some reactions tliat take place are exothermic, and some are endothermic. A reacti()n that reaches a measurable equilibrium may be caused to go in either direction, by starting with one set of reactants or another. For example, the reaction involving tiie red gas nitrogen dioxide and the colorless gas dinitrogen tetroxide has a heat effect shown by the following equation ... 

Dinitrogen tetroxide (N2O4), which is in equilibrium with nitrogen dioxide. 

Absorber performance is controlled by temperature and pressure. At reduced temperatures the gas-phase equilibrium moves toward the formation of dinitrogen tetroxide and an increased solubility in HNO3. Therefore, lower temperatures improve the absorption rate and increase the acid concentration. At higher pressures the NO oxidation reaction is quicker, and equilibrium moves toward nitrogen dioxide. In addition, with higher pressure more concentrated nitric acid is produced. 

P12.6 The dissociative gas and important rocket propellant dinitrogen tetroxide is in rapid equilibrium with nitrogen dioxide following the reaction ... 

The reversible reaction between dinitrogen tetroxide (N2O4) and nitrogen dioxide (NO2), depicted with space-filling models in Figure 10.1, is an example of a chemical equilibrium. The progress of the reaction... 

Nitrogen dioxide, NO2, a red gas, and its dimer dinitrogen tetroxide, N2O4, a colorless, easily condensable gas, exist in equilibrium with one another ... 

The nitric oxide which is formed reacts with oxygen to form nitrogen dioxide. Nitrogen dioxide exists in equilibrium with its dimer, dinitrogen tetroxide. The nitrogen dioxide/dimer mixture is sent to a column, sometimes called an absorption tower. Water is added at the top of the column. The nitrogen dioxide is converted to nitric acid. Byproduct nitric oxide is oxidized to nitrogen dioxide by means of a stream of air passed into the absorption column. The aqueous nitric acid is removed continuously from the base of the column. Overall, the reaction can be written as ... 

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