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Potassium chromate
Potassium-chromate-sample.jpg
IUPAC name
Other names Chromic acid, (H2CrO4), dipotassium salt
Identifiers
CAS number 7789-00-6 Yes check.svgY
PubChem 24597
EC number 232-140-5
RTECS number GB2940000
Properties
Molecular formula CrK2O4
Molar mass 194.19 g mol−1
Appearance Yellow odorless powder
Odor odorless
Density 2.7320 g/cm3
Melting point

968 °C, 1241 K, 1774 °F

Boiling point

1000 °C, 1273 K, 1832 °F

Solubility in water 63 g/100 mL (20 °C)
Solubility insoluble in alcohol
Hazards
MSDS Chemical Safety Data
EU Index 024-006-00-8
EU classification Carc. Cat. 2
Muta. Cat. 2
Toxic (T)
Irritant (Xi)
Dangerous for the environment (N)
R-phrases R49, R46, R36/37/38, R43, R50/53
S-phrases S53, S45, S60, S61
NFPA 704
NFPA 704.svg
0
3
1
OX
Related compounds
Other anions Potassium dichromate
Potassium molybdate
Potassium tungstate
Other cations Sodium chromate
Calcium chromate
Barium chromate
 Yes check.svgY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Potassium chromate (K2CrO4) is a yellow chemical indicator used for identifying concentrations of chloride ions in a salt solution with silver nitrate (AgNO3). It is a class two carcinogen and can cause cancer on inhalation.[1]

Contents

General information

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Physical properties

Potassium Chromate is a lemon yellow compound that is in the form of a crystalline solid, and it is very stable.

Reactions

When reacted with Lead(II) Nitrate, it creates an orange-yellow precipitate, Lead(II) Chromate, Silver Nitrate, and Potassium Nitrate. All ions hydrolyze in solution.

Occurrence

Tarapacaite is the natural, mineral form of potassium chromate. It occurs very rarely and until now is known from only few localities on Atacama desert.

Dangers/Hazards

Potassium Chromate is very toxic and may be fatal if swallowed. It may also act as a carcinogen, and can create reproductive defects if inhaled or swallowed. It also is a strong oxidizing agent if in the presence of H+ to produce the dichromate ion. It may react rapidly, or violently. It is also possible that it may react explosively with other reducing agents and flammable objects.

References

  1. ^ Potassium chromate information URL last accessed 15 March 2007

Simple English

[[File:|thumb|Potassium chromate]] Potassium chromate is a chemical compound. Its chemical formula is K2CrO4. It has potassium and chromate ions.

Contents

Properties

It is a yellow crystalline solid. It is an oxidizing agent in an acidic condition. It is toxic though, because it contains chromium in its +6 oxidation state. It can be destroyed by reaction with reducing agents. It is very rarely found in the ground. It reacts with lead nitrate to make lead chromate, a yellow pigment.

Preparation

It is made by reacting chromium trioxide with potassium hydroxide. It can also be made by oxidation of potassium hydroxide and chromium(III) oxide.

Occurrence

Potassium chromate is found very rarely as a mineral. It dissolves easily in water. It is only found in very dry places.

Uses

It is used to test for chloride ions. It can also be used to make lead chromate for paint.

Safety

Potassium chromate is very toxic. It is a carcinogen. It reacts with reducing agents violently when in acid.

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