Difference Between Nitrate and Nitrite

Main Difference -Nitrate vs Nitrite

Both Nitrates and Nitrites are inorganic chemical compounds, and as the names imply, the characteristic element in them is ‘N’ or Nitrogen, which has an atomic number of 7. Nitrogen is an odourless diatomic gas in nature and is reactive. The element Nitrogen is also highly electro-negative. And both Nitrates and Nitrites are two important classes of Nitrogen-containing compounds. The main difference between Nitrate and Nitrite is that Nitrate group contains one Nitrogen atom and three Oxygen atoms whereas Nitrite group contains one Nitrogen atom and two Oxygen atoms. 

What is Nitrate

Nitrate is a polyatomic ion made of Nitrogen and Oxygen atoms. The chemical structure contains one Nitrogen atom and three Oxygen atoms and is represented by the molecular formula NO3-. The nitrate group can be described as a functional group in inorganic chemistry. The compound has a trigonal planar geometry. This tells us how the atoms within the compound is arranged in three-dimensional space. According to the structure of the Nitrate, Nitrogen is the centre and is bonded to three identical Oxygen atoms. However, at any given time, only one oxygen atom is doubly bonded to the Nitrogen centre, the other two Oxygen atoms are bonded through single bonds. But, as the three oxygen atoms are identical to each other, it is believed that the structure is in accordance with the resonance principle in chemistry. Therefore, it suggests that the double bond can migrate between any Oxygen atom and the Nitrogen centre. Also, Nitrogen has an oxidation number of +5 in Nitrates.

Nitrate ions have an overall charge of -1, however considering the charge distribution within the ion, the Nitrogen atom carries a charge of +1, and each Oxygen atom carries a charge of -(2/3), to result in an overall charge of -1. Generally, all nitrate salts are soluble in water. With water, the Nitrate ions form nitric acid, which is considered as a strong acid. Nitrate compounds are used for fertilizers in agriculture, for the production of explosives and gun powder, etc.

What is Nitrite  

Nitrites is also a polyatomic ion containing N and O atoms, where Nitrogen has an oxidation number of +3. The Nitrite group contains one Nitrogen atom and two Oxygen atoms and is represented by the molecular formula, NO2-. The O-N-O bond angle is roughly around 120°. This gives us an idea how the atoms are arranged in three-dimensional space. Nitrite ions can be oxidized to form Nitrates since the oxidation number of Nitrogen in Nitrites is less than that of Nitrates.

Upon reacting with water, Nitrites form nitrous acid, which is considered to be a weak acid in inorganic chemistry. In the chemical structure of the Nitrite compound, one Oxygen atom is doubly bonded to the Nitrogen centre, and the other is singly bonded. However, as the resonance principle governs the structure relationship of the group, the double bond between the Oxygen atom and the Nitrogen atom is considered to be constantly migrating; hence, the two Oxygen atoms would have identical status. Nitrites are produced by nitrifying bacteria and is often used in the food industry for the curing of meat. It also has an important biochemical role being the vasodilator for nitric oxide.

Difference Between Nitrate and Nitrite

Definition

Nitrate is an inorganic polyatomic ion carrying a charge of -1, made of one Nitrogen atom and three Oxygen atoms.

Nitrite is an inorganic polyatomic ion carrying a charge of -1, made of one Nitrogen atom and two Oxygen atoms.

Oxidation Number

The oxidation number of Nitrogen in Nitrates is +5.

The oxidation number of Nitrogen in Nitrites is +3.

Molecular Shape

Nitrates have a trigonal planar geometry.

Nitrites have a bent molecular geometry.

Reaction with Water

Nitrates form nitric acid which is a strong acid.

Nitrites form nitrous acid which is a weak acid.

Oxidation and Reduction

Nitrates can be reduced to form nitrites.

Nitrites can be oxidized to form nitrates.

Image courtesy:

“Nitrate-3D-balls” by Benjah-bmm27 – Own work. (Public Domain) via Commons

“Nitrite-3D-vdW”. (Public Domain) via Commons

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