- What it is. This nitric acid solution is a 6.0 N (6.0 M) standardized-strength acid, supplied in a 500 mL size. It is a clear, colorless, corrosive oxidizing acid used for digestion, metal dissolution, and qualitative analysis.
- Molar equals normal. Nitric acid releases one hydrogen ion per molecule, so 6.0 N equals 6.0 M. Each liter contains about 378 g of nitric acid, and each milliliter neutralizes 6.0 millimoles of base (calculated).
- How it compares with concentrated acid. Concentrated 70% nitric acid is about 15.8 M (calculated), so 6 N acid is roughly a 38% dilution by volume. It fumes far less than concentrated acid but remains corrosive and oxidizing.
- An oxidizing acid. Unlike hydrochloric acid, nitric acid oxidizes as well as acidifies. It dissolves copper, silver, and other metals that hydrochloric acid cannot, releasing nitrogen oxides, and it keeps metals in solution as soluble nitrates for analysis.
- Laboratory uses. Six-normal nitric acid dissolves metals and alloys, digests samples for elemental analysis, acid-washes labware for trace-metal work, acidifies samples, and is used in classic qualitative analysis schemes that separate metal ions.
- Why a defined 6 N strength. Diluting concentrated acid releases heat and fumes and introduces variation. A prepared 6.0 N solution gives consistent strength for methods that specify it and avoids handling concentrated acid for routine work.
- Acid washing labware. For trace-metal analysis, labware is commonly soaked in dilute nitric acid, then rinsed thoroughly with deionized water, which strips metals adsorbed on glass and plastic surfaces and lowers analytical blanks.
- Reactions with metals. Nitric acid reacts with copper to form blue copper(II) nitrate and brown nitrogen dioxide gas, a classic demonstration of its oxidizing power. Gold and platinum resist nitric acid alone and need aqua regia, a mixture with hydrochloric acid.
- Handling at a glance. Nitric acid causes severe skin burns and turns skin yellow on contact. Work in a fume hood, wear chemical splash goggles and acid-resistant gloves, and keep it away from organic materials and solvents, which can react violently with nitric acid.
- Related products. For concentrated acid, see Lab Pro's Nitric Acid 70%, ACS Grade (500 mL, 2.5 L). Lab Pro's guide on storing nitric acid safely covers storage and segregation.
Technical Specifications
| Chemical Name | Nitric acid, aqueous solution |
| CAS Numbers | 7697-37-2 (nitric acid); 7732-18-5 (water) |
| EC Number (HNO3) | 231-714-2 |
| Synonyms | Aqua fortis (concentrated), hydrogen nitrate, azotic acid |
| Formula (active) | HNO3 |
| Molecular Weight (active) | 63.01 g/mol |
| Concentration | 6.0 N (6.0 M) |
| HNO3 Content | About 378 g/L (calculated) |
| Neutralizing Capacity | 1.00 mL = 6.00 mmol base (calculated) |
| Appearance | Clear, colorless liquid |
| Physical State | Liquid, aqueous solution |
| Hazard Profile | Corrosive; oxidizing; causes severe burns (confirm on SDS) |
| DOT | UN2031, Nitric acid, Class 8; SDS |
| Exposure Limits | OSHA PEL 2 ppm TWA; NIOSH REL 2 ppm TWA, 4 ppm STEL |
| Package Size | 500 mL |
Applications / Common Uses
- Metal dissolution: Dissolves copper, silver, and alloys.
- Sample digestion: Prepares samples for elemental analysis.
- Labware acid washing: Removes trace metals from glass and plastic.
- Qualitative analysis: Supports classic metal ion separations.
- Sample acidification: Acidifies water samples for metals testing.
Storage, Handling & Shipping
Caution: 6 N nitric acid is corrosive and oxidizing. It causes severe skin burns and eye damage, stains skin yellow, and can react violently with organic materials. Handle in a fume hood with chemical splash goggles and acid-resistant gloves.
Store tightly closed in a cool, ventilated acid cabinet dedicated to oxidizing acids, separated from organic acids, flammables, bases, metals, and reducing agents. When diluting, always add acid slowly to water.
- Incompatible materials: Organic materials and solvents, acetic acid and other organic acids, bases, reducing agents, metal powders, and cyanides or sulfides.
- Exposure limits: OSHA PEL 2 ppm TWA; NIOSH REL 2 ppm TWA, 4 ppm STEL.
- Spill response: Ventilate, contain with inert non-combustible absorbent, and neutralize with sodium bicarbonate or an acid spill kit.
- First aid: Skin or eyes: flush with water for at least 15 minutes and seek medical attention. Inhalation: move to fresh air; symptoms may be delayed.
Related Categories & Services
- Shop Acids for related products in this category.
- Explore Buffers, Standards & Solutions and ACS Grade Laboratory Chemicals.
- Vendor Managed Inventory (VMI) Program: Lab Pro can stock, track, and replenish this item on site so it never runs out. Contact info@labproinc.com or 888-452-2776 to set up a VMI assessment.
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FAQs
Is 6 N nitric acid the same as 6 M?
Yes. Nitric acid releases one hydrogen ion per molecule, so its normality equals its molarity. A 6.0 N solution is 6.0 M, containing about 378 g of nitric acid per liter, and each milliliter neutralizes 6.0 millimoles of a monobasic base. Diprotic acids such as sulfuric acid differ.
What is 6 N nitric acid used for?
It dissolves metals and alloys, digests samples for elemental analysis, acid-washes labware for trace-metal work, acidifies samples, and supports classic qualitative analysis schemes. Its defined strength gives consistent results for methods that specify 6 N acid without handling concentrated acid. It also oxidizes as it acidifies, which helps dissolve metals that other acids cannot attack.
Why does nitric acid turn skin yellow?
Nitric acid reacts with proteins in skin to form yellow nitrated compounds, a reaction known as the xanthoproteic reaction. A yellow stain means the acid has contacted skin, so rinse immediately with plenty of water and seek medical attention for any burn. The stain fades as skin renews.
Why must nitric acid be kept away from organic materials?
Nitric acid is a strong oxidizer that can react violently with organic solvents, acetic acid, and other combustible materials, sometimes causing fire or explosion. Store it in a dedicated acid cabinet away from organics, and never mix nitric acid waste with organic waste. Keep separate waste containers.
How do I dilute 6 N nitric acid to 1 N?
Add 1 part 6.0 N nitric acid slowly to 5 parts deionized water, for example 166.7 mL acid diluted to 1 liter. Work in a fume hood, mix and cool the solution, and standardize the result if your method requires an exact concentration. Label the diluted solution clearly.
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