Potassium sodium tartrate

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Potassium sodium tartrate
Potassium sodium tartrate bottle and sample.jpg
Potassium sodium tartrate aka Rochelle salt
Names
IUPAC name
Sodium potassium L(+)-tartrate tetrahydrate
Other names
E337
Rochelle salt
Seignette salt
Properties
KNaC4H4O6·4H2O
Molar mass 282.1 g/mol
Appearance Large colorless monoclinic needles
Odor Odorless
Density 1.79 g/cm3
Melting point 75 °C (167 °F; 348 K)
Boiling point 220 °C (428 °F; 493 K) (decomposes)
26 g/100 ml (0 °C)
47.4 g/100 ml (6 °C)
66 g/100 ml (26 °C)
Solubility Insoluble in acetone, ethanol
Vapor pressure ~0 mmHg
Hazards
Safety data sheet Sigma-Aldrich (tetrahydrate)
Related compounds
Related compounds
Tartaric acid
Potassium antimony tartrate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Potassium sodium tartrate (tetrahydrate), more commonly known as Rochelle Salt, is a double salt of tartaric acid first prepared (around 1675) by an apothecary, Pierre Seignette, of La Rochelle, France.

Properties

Chemical

Addition of a strong acid, like hydrochloric acid will give tartaric acid.

Physical

Potassium sodium tartrate is a white crystalline solid, soluble in water.

Uses

  • Potassium Sodium Tartrate is used in the preparation of Biuret reagent.
  • Potassium Sodium Tartrate is used in the the preparation of Fehling's Solution
  • Potassium Sodium Tartrate is used in "crystal" microphones.
  • Potassium Sodium Tartrate is used as an alkaline buffer.
  • Potassium Sodium Tartrate has been used as a laxative.

Availability

Potassium sodium tartrate is readily available on EBay.

Preparation

Can be prepared from tartaric acid.

Projects

Handling

Safety

Can be irritating to skin.

Storage

Potassium sodium tartrate is very deliquescent and should be stored in a sealed container.

Disposal

Dissolve in large excess of water and put down drain.

References

Relevant Sciencemadness threads