nitric acid

Nitric acid is a compound. Pure nitric acid is a colorless liquid with a pungent odor, and concentrated nitric acid is a mixture. The mass fraction of commercially available concentrated nitric acid is about 68%, the density is about 1.4 g/cm³, and the boiling point is 83°C. It is volatile and can be dissolved in any proportion. Water, similar to sulfuric acid, releases a lot of heat when miscible, so constant stirring is required, and only concentrated nitric acid can be added to water, not the other way around. Nitric acid with a concentration of 98% (86~97.5%) is called "fuming nitric acid" because this acid is more volatile and forms white mist when exposed to humid air. It is corrosive and toxic. Be careful to wear polyethylene plastic gloves and special Face mask.

Concentrated nitric acid and dilute nitric acid:

1. Add iron or aluminum to cold nitric acid. If there is no obvious phenomenon, it is concentrated nitric acid. If bubbles appear on the surface of iron or aluminum, it is dilute nitric acid.

2. Looking at it directly, the white mist is concentrated nitric acid, and the white mist is dilute nitric acid. Here we take advantage of the volatility of nitric acid (concentrated hydrochloric acid is also volatile)

*Note: Since nitric oxide oxidizes quickly, this method requires sealing.

In fact, the most intuitive method is to measure concentration.

Safety measures:

Never inhale fumes, vapors or sprays.

If it comes into contact with your eyes or skin, wash it immediately with plenty of water and seek medical treatment as soon as possible.

All contaminated clothing must be removed immediately.

Wear appropriate protective clothing, protective gloves and masks.

When storing concentrated nitric acid, it should be separated from reducing substances.

Concentrated nitric acid:

Dilute nitric acid: