Formation of Nitrogen Dioxide

2NO + O₂ → 2NO₂

Overview

Nitric oxide reacts with oxygen in the atmosphere to form nitrogen dioxide, a reddish-brown toxic gas. This reaction is central to atmospheric chemistry and smog formation. It occurs rapidly at room temperature without any catalyst needed.

Participants

Role	Substance	Coefficient	State
Product	Nitrogen Dioxide NO₂	2	(g)

Everyday Example

The brown haze visible over cities on smoggy days is largely due to nitrogen dioxide formed by this reaction from vehicle exhaust.

Industrial Importance

This is a key step in the Ostwald process for nitric acid production. Managing NOx emissions is a major environmental and regulatory concern for power plants and vehicles.

Properties

Type: Synthesis
Reversible: Yes
Energy: Exothermic
ΔH: -114.2 kJ/mol

Related Reactions

Fischer-Tropsch Synthesis (General) Formation of Aluminum Oxide Formation of Ammonia (Haber Process) Formation of Barium Oxide Formation of Barium Sulfate Formation of Beryllium Oxide Formation of Cadmium Oxide Formation of Calcium Carbonate from Oxides Formation of Calcium Hydroxide Formation of Calcium Oxide (Quicklime)

Frequently Asked Questions

What is the equation for Formation of Nitrogen Dioxide?

The balanced equation is: 2NO + O₂ → 2NO₂.

What type of reaction is Formation of Nitrogen Dioxide?

Formation of Nitrogen Dioxide is a synthesis reaction. It is reversible under certain conditions.

Is Formation of Nitrogen Dioxide exothermic or endothermic?

Formation of Nitrogen Dioxide is exothermic (releases energy). The enthalpy change (ΔH) is -114.2 kJ/mol.