Monopotassium phosphate

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Monopotassium phosphate
Monopotassium phosphate potassium dihydrogen phosphate sample.jpg
MKP from a pet shop.
Names
IUPAC name
Potassium dihydrogen phosphate
Other names
Potassium phosphate monobasic
KDP
Identifiers
Jmol-3D images Image
Properties
KH2PO4
Molar mass 136.086 g/mol
Appearance White crystalline powder
Odor Odorless
Density 2.338 g/cm3
Melting point 252.6 °C (486.7 °F; 525.8 K)
Boiling point 400 °C (752 °F; 673 K) (decomposes)
22.6 g/100 mL (20 °C)
83.5 g/100 mL (90 °C)
Solubility Slightly soluble in ethanol, methanol
Insoluble in benzene, dichloromethane
Acidity (pKa) 6.86
Hazards
Safety data sheet ScienceLab
Flash point Non-flammable
Related compounds
Related compounds
Dipotassium phosphate
Tripotassium phosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Monopotassium phosphate (MKP) or potassium dihydrogen phosphate (KDP) is a soluble phosphoric acid salt of potassium with the chemical formula KH2PO4.

Properties

Chemical

Reacting MKP with 1 mole of potassium hydroxide will produce dipotassium phosphate, and further adding phosphoric acid will convert it to tripotassium phosphate:

KH2PO4 + KOH → K2HPO4 + H2O
K2HPO4 + KOH → K3PO4 + H2O

Physical

Potassium dihydrogen phosphate is a white solid, soluble in water. It decomposes when heated above 400 °C. MPK's density is 2.338 g/cm3 at standard conditions.

Availability

MKP is sold in some agricultural stores as fertilizer.

It can also be purchased from pet shops.

Preparation

Potassium phosphate monobasic can be made by reacting phosphoric acid with potassium hydroxide.

Projects

Handling

Safety

MPK is safe to handle and poses little toxicity.

Storage

MKP doesn't require special storage and can be stored in any container.

Disposal

MKP can be dumped in the ground or poured down the drain.

References

Relevant Sciencemadness threads