1. Pharmaceuticals

• Synthesis of APIs: Nitric acid is used to introduce nitro groups into organic molecules, which are then used to synthesize various pharmaceutical compounds. 
• Quality control: It helps in the analysis of pharmaceutical products to ensure their purity and quality. 
• Homoeopathic medicine preparation: Nitric acid is used in the potentization process, which is part of the preparation of homoeopathic medicines. 

2. Agrochemicals

• Fertilizer Production: Nitric acid is a crucial ingredient in the production of various fertilizers, particularly nitrogenous fertilizers like ammonium nitrate and calcium nitrate. Ammonium nitrate is a major component of many commercial fertilizers and is often used to enhance plant growth. It's a key component in manufacturing ammonium nitrate, a widely used nitrogen-based fertilizer. 
• Ph Adjustments: The acidic nature of nitric acid is useful in adjusting the pH of solutions, ensuring that the water and fertilizers are in the optimal range for plant uptake.

3. Performance chemicals

• Nitration: Nitric acid is used to introduce the nitro group (-NO2) into organic molecules, a process called nitration. This reaction is a key step in the production of explosives like nitroglycerin and TNT. Nitration reactions can also be used to synthesize dyes and other organic compound.
• Purification: Nitric acid, especially when combined with hydrochloric acid as aqua regia, is used to purify noble metals like gold and platinum. Aqua regia can dissolve these metals, allowing for their separation and purification from impurities.

4. Metal treatment

• Oxidation and Dissolution: Nitric acid can dissolve most metals by oxidizing them and converting them into soluble metal nitrates. This property is crucial in processes like metal parting, where silver is selectively dissolved from gold alloys. It's also used to convert metals to different oxidized forms, like copper to cupric nitrate.
• Passivation: Nitric acid passivation is a traditional method of creating a protective oxide layer on metal surfaces, particularly stainless steel and titanium. This process helps to prevent corrosion by removing free iron from the surface. Nitric acid passivation is often preferred for its established process and ability to optimize performance with different grades of stainless steel.

5. Water treatment

• pH Control: Nitric acid is added to neutralize alkaline wastewater, bringing the pH to the desired level for safe discharge or reuse.
• Metal Removal: It helps remove heavy metals from wastewater by forming insoluble compounds, facilitating their removal through processes like precipitation or filtration.
• Cleaning and Descaling: Nitric acid is used to clean and remove scale from industrial equipment, ensuring efficient operation.
• Oxidation Processes: In advanced treatment, it acts as an oxidizing agent, helping to break down organic compounds and other contaminants.