Key Specifications for $\text{Nitric Acid} (\approx 69-70\% \text{ Assay})$
| Parameter | Specification (Example Range) | Notes |
| Assay ($\text{HNO}_3$ content) | $69 – 70.0\%$ | This is the primary measure of concentration. |
| Appearance | A clear, colorless liquid | May appear yellow due to dissolved $\text{NO}_2$. |
| Colour scale | Max 10 APHA | Measures the yellowness. |
| Weight/ $\text{mL}$ at $20^\circ\text{C}$ | $1.41 – 1.42 \text{ g}$ | Related to density. |
| Residue on ignition | Max $0.0005\%$ | Indicates non-volatile impurities. |
| Chloride ($\text{Cl}$) | Max $0.00005\%$ | Low limit for high-purity grades. |
| Sulphate ($\text{SO}_4$) | Max $0.0001\%$ | Low limit for high-purity grades. |
| Iron ($\text{Fe}$) | Max $0.00002\%$ | Low limit for high-purity grades. |
| Heavy metal (as $\text{Pb}$) | Max $0.00002\%$ | Limits for metallic impurities. |
Properties and Other Grades
- Molecular Formula: 3$\text{HNO}_3$
- Molecular Weight: 4$63.01 \text{ g/mol}$
- pH Value: 5$\approx 1$ (for the solution)6
- Boiling Point: 7$\approx 122^\circ\text{C}$ (for 8$69\%$ solution)9
- Density: 10$\approx 1.41 \text{ g/cm}^3$ (for 11$69\%$ solution at 12$20^\circ\text{C}$)13
- Solubility in Water: Infinitely soluble.14
White Fuming Nitric Acid ($\text{WFNA}$):
- Has a maximum of $2\%$ water.
- Has a maximum of $0.5\%$ dissolved $\text{NO}_2$ (Nitrogen Dioxide).
Red Fuming Nitric Acid ($\text{RFNA}$):
- Concentration is typically around 15$84\%$ 16$\text{HNO}_3$, with the rest mainly being 17$\text{N}_2\text{O}_4$ (Dinitrogen tetroxide).18
Common Applications
Nitric acid is a vital industrial chemical, primarily used for:
- Fertilizer Production: Producing ammonium nitrate (19$\text{NH}_4\text{NO}_3$), which accounts for the majority of its use.20
- Chemical Synthesis: Used for nitration to make explosives (like 21$\text{TNT}$), dyes, and intermediates for polymers (like nylon precursors).22
- Oxidizing Agent: Used in metallurgy (e.g., etching, refining noble metals), and as a rocket propellant oxidizer in concentrated forms.23
Would you like me to find the typical specifications for a specific concentration or grade of nitric acid?
Video on uses of Nitric Acid
This video discusses the various industrial uses of nitric acid, which often dictate the required purity specifications.
