Ammonium bisulfite

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Not to be confused with ammonium bisulfate.
Ammonium bisulfite
Ammonium bisulfite by Shiva Chemist.jpg
NH4HSO3 crystals
Names
IUPAC name
Ammonium hydrogen sulfite
Other names
Ammonium hydrogensulphite
Azanium hydrogen sulfite
Sulfurous acid, ammonium salt (1:1)
Properties
NH4HSO3
Molar mass 99.104 g/mol
Appearance Colorless to yellowish solid
Odor Poignant, sulfur dioxide
Density 2.03 g/cm3 (at 20 °C) (72% aq. sol.)
Melting point 50–60 °C (122–140 °F; 323–333 K) (decomposes)
Boiling point 147–150 °C (297–302 °F; 420–423 K) (sublimes)
71.8 g/100 ml (0 °C)
267 g/100 ml (10 °C)
620 g/100 ml (60 °C)
Solubility Reacts with HCl 37%
Insoluble in toluene
Hazards
Safety data sheet Hydrite (70%)
Related compounds
Related compounds
Ammonium sulfite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ammonium bisulfite is an inorganic compound, with the formula NH4HSO3. It is a pale yellow solid, which emits toxic sulfur dioxide fumes at standard conditions.

Properties

Chemical

Ammonium bisulfite will slowly oxidize in air to ammonium bisulfate:

NH4HSO3 + ½ O2 → NH4HSO4

Addition of excess ammonia will give ammonium sulfite.

NH4HSO3 + NH3 → (NH4)2SO3

Physical

Ammonium bisulfite is an unstable white-yellowish solid, soluble in water, which gives off sulfur dioxide vapors upon standing, giving it a very unpleasant odor.

Availability

Ammonium bisulfite is available as aqueous solution, though due to its hazards it's best to make it yourself.

Preparation

Can be prepared by bubbling an excess of sulfur dioxide through aqueous ammonia. Cooling the solution will cause crystals to precipitate.[1]

Projects

  • Reducing agent

Handling

Safety

Ammonium bisulfite is irritant and toxic. Should be handled with proper protection, in well ventilated areas.

Storage

In closed bottles, away from metals, in well ventilated areas. Do not store for long.

Disposal

Can be neutralized with hydrogen peroxide to ammonium bisulfate and if necessary with excess ammonia to ammonium sulfate.

References

  1. https://www.youtube.com/watch?v=EX9j04RNkz0

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