How is ammonia and nitric acid extracted and prepared

Nitrogen gas ($\text{N}_2$) is obtained from the air (which is about 78% nitrogen). Hydrogen gas ($\text{H}_2$) is typically obtained from the steam reforming of natural gas (methane, $\text{CH}_4$) or from the electrolysis of water.

The reaction occurs at high temperatures (typically $400-450^\circ\text{C}$) and high pressures (typically $150-250$ atmospheres). An iron catalyst (often with promoters like potassium oxide and aluminum oxide) is used to increase the reaction rate.

Nitrogen and hydrogen react reversibly to form ammonia.

The ammonia produced is then cooled and liquefied, separating it from unreacted nitrogen and hydrogen, which are recycled.

Nitric Acid ($\text{HNO}_3$)

Nitric acid is primarily prepared industrially through the Ostwald process.

Ammonia gas is mixed with air (oxygen) and passed over a platinum-rhodium catalyst at high temperatures ($800-900^\circ\text{C}$). This oxidizes ammonia to nitrogen monoxide ($\text{NO}$).

The hot nitrogen monoxide is then cooled and reacted with excess oxygen (from the air) to form nitrogen dioxide ($\text{NO}_2$).

Nitrogen dioxide is absorbed in water in an absorption tower, where it reacts to form nitric acid and nitrogen monoxide. The nitrogen monoxide is recycled back into the process.

This process typically yields concentrated nitric acid (around 68% by mass).