Nitrate vs. Nitrite

Difference Between Nitrate and Nitrite

Both nitrate and nitrite are anions of nitrogen and in spite of the similarity that appear to exist between them, there lie a lot of differences between them. These differences may be in terms of their structure, bonding, geometry, oxidation state, chemical reactivity, the use and many more. These differences are mainly discussed here.

NO3-ion is the conjugate base of HNO3 (nitric acid) which is a strong acid. This is a planer molecule which is in sp 3 hybridization state of the nitrogen atom and where all three atoms of O2 atoms are equivalent. It consists of 24 electrons in the valence shells. The NO3-ion has a molecular weight of 62,004 g mol-1.

NO2-ion is the conjugate base of HNO2 (III nitric acid) which is a weak acid (ph value of 3.5). It has also one molecule in planer state with sp2 hybridization. In the valence shells, there are only 18 electrons. The NO2-ion was the molecular weight of 46,006 g mol-1.

When the bonding in both the ions is considered, the NO3-pi bonding exhibits four 2pz atomic orbital (one N and three orbital of three oxygen atoms). The four atomic orbital forms 4, molecular orbital which are four-centered. The orbital with the lowest energy orbital is the bonding orbital and the one with the higher energy is anti-bonding in nature. Other two orbital are degenerate (equal in energy) which are non-bonding orbital. In the NO2-ion, the bonding involves only three 2pz atomic orbital. Here, the orbital with the lowest energy orbital is bonding one, the middle one is the non-bonding orbital and the other is the anti-bonding orbital. In both ions, the bonding orbital involve in  building the obligation (the sigma-bond) and non-bonding orbital is involved in the realization π – bonds (bonds devotees). So in the NO3-ion each bond has an obligation of the order 11 / 3.1. In the NO2-ion, the order of duty is 11 / 2. 1 and the obligation are of half bonds.

Although both ions are of the same geometry, the order requirement is varies as their geometric shapes are also different. The NO3-ion has a triangular form of planer and NO2-ion has an angular shape (or V-shaped). The bond angles are also different. The angle of obligation ONO ion NO3-and NO2-ion is 1200 and 1150 respectively. The oxidation state of nitrogen in both the NO3-ion in the NO2-ion is 5 and 3 respectively. Because of these reasons (especially the difference in bonding), chemical reactivity (such as basicity, by oxidizing / reducing capacity, thermal decomposition products consist of speakers of these ions) is also different.

In practice, NO2-ion is a weaker base while the NO3-ion is a very low base. When the oxidation state of nitrogen atoms in these ions is included for consideration, NO2-ion can act as a reducing agent as well as an oxidizing agent while the NO3-ion may only act as an oxidizing agent.

Examples for products obtained from the thermal decomposition of NO3-and NO2-ions containing the speakers are given below to show the difference in responsiveness.

Even when they form complexes with metal ions they behave in a different way. Thus, NO2-l’ion acts as monodentate ligand while the NO3-ion acts as a bidentate ligand.

These differences in chemical reactivity help us to use them for different uses. For example, nitrates are used in explosives production and nitrites are mostly employed in the treatment of meat (however, sometimes nitrates may also be used) and. Nitrates occur naturally and are cancerous. But Nitrites are not cancerous.

 

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