Potassium dihydrogen phosphate Formula – Structure, Properties, Uses, Sample Questions

Potassium dihydrogen phosphate consists of the elements Potassium, Hydrogen, Phosphorous, and Oxygen. Potassium is a silvery-white soft metal present in group 1 of the periodic table. Its atomic number is 19 and is represented by the symbol K. Hydrogen is the lightest, colorless, odorless, tasteless, and flammable gas. Its atomic number is 1 and is represented by the symbol H. Phosphorus is a highly reactive nonmetal present in group 15 of the periodic table. Its atomic number is 15 and is represented by the symbol P. Oxygen is a highly reactive nonmetal present in group 16 of the periodic table. Its atomic number is 8 and is represented by the symbol O.

Potassium Dihydrogen Phosphate

Potassium dihydrogen phosphate is a soluble, inorganic phosphate and potassium salt where dihydrogen phosphate is the counterion. The molecular formula of Potassium dihydrogen phosphate is KH₂PO₄. It is a source of Phosphorous and Potassium. Potassium dihydrogen phosphate is prepared by the reaction of phosphoric acid with potassium carbonate. It has various applications in the field of agriculture, the foods industry, pharmaceuticals, etc. The other names for Potassium dihydrogen phosphate are Monopotassium Phosphate, Potassium biphosphate. The pH value of this compound lies between 4.4 and 4.7

Preparation of Potassium Dihydrogen Phosphate

• Potassium Dihydrogen Phosphate is prepared by the reaction between Phosphoric acid and Potassium Hydroxide. The chemical reaction is given below-

H₃PO₄ + KOH ⇢ KH₂PO₄ + H₂O

• It can also be prepared by the reaction between Phosphoric acid and Potassium Carbonate. This reaction gives Potassium Dihydrogen Phosphate, water, and carbon dioxide.

2H₃PO₄ + K₂CO₃ ⇢ 2KH₂PO₄ + H₂O + CO₂

• Potassium Dihydrogen Phosphate can be derived from Dipotassium hydrogen phosphate by reacting with Phosphoric acid.

K₂HPO₄ + H₃PO₄ ⇢ 2KH₂PO₄

Structure of Potassium dihydrogen phosphate

Potassium dihydrogen phosphate structure

Physical Properties of Potassium dihydrogen phosphate

• The appearance of Potassium dihydrogen phosphate is white/colorless powder.
• Molecular weight of Potassium dihydrogen phosphate is 136.086 g/mol
• Its melting point is 252.6 °C.
• Boiling point of Potassium dihydrogen phosphate is 400 °C.
• Density of Potassium dihydrogen phosphate is 2.338 g/cm³.
• It is soluble in water.

Chemical Properties of Potassium dihydrogen phosphate

• Potassium dihydrogen phosphate dissolves in water to form phosphoric acid and potassium hydroxide. The reaction is given below 

KH₂PO₄ + H₂O ⇢ H₃PO₄ + KOH

• Potassium dihydrogen phosphate reacts with Sodium hydroxide to give Disodium phosphate, Potassium hydroxide, and water.

KH₂PO₄ + 2NaOH ⇢ Na₂HPO₄ + KOH + H₂O

Uses of Potassium dihydrogen phosphate

• Potassium dihydrogen phosphate is used in the food industry as a food addict.
• It is also used in pharmaceuticals.
• It is used in the agriculture field, as a buffering agent, in fertilizers.
• Used in various cosmetic products.
• Also used in manufacturing fertilizers.

Sample Questions

Question 1: What happens when Potassium dihydrogen phosphate reacts with bases like NaOH?

Answer:

Potassium dihydrogen phosphate reacts with bases like Sodium Hydroxide to produce Disodium phosphate, Potassium hydroxide and water.

KH₂PO₄ + 2NaOH ⇢ Na₂HPO₄ + KOH + H₂O

Question 2: Find the molar mass of Potassium dihydrogen phosphate.

Answer:

The molecular formula of Potassium dihydrogen phosphate is KH₂PO₄.

Atomic weight of Potassium = 39.0983

Atomic weight of each Hydrogen = 1.00784

Atomic weight of Phosphorus = 30.973762

Atomic weight of each Oxygen = 15.999

Molecular weight of KH₂PO₄ = 39.0983 + (2 × 1.00784) + 30.973762 + (4 × 15.999)

=136.08

Question 3: What are the applications of Potassium dihydrogen phosphate?

Answer:

Potassium dihydrogen phosphate is used in food industry as a food addict, in pharmaceuticals. It is also used in manufacturing fertilizers, cosmetic products.

Question 4: Is Potassium Dihydrogen Phosphate a hazardous compound?

Answer:

Potassium dihydrogen phosphate is considered as the mild hazardous substance. It cause skin, eye and respiratory tract irritation. Intake of large quantity causes nausea, vomiting, diarrhoea.

Question 5: How Potassium Dihydrogen Phosphate is synthesized?

Answer:

Potassium dihydrogen phosphate (KH₂PO₄) is prepared by the reaction of phosphoric acid (H₃PO₄) on potassium carbonate (K₂CO₃). 

2H₃PO₄ + K₂CO₃ ⇢ 2KH₂PO₄ + H₂O + CO₂

Question 6: Why do Potassium Dihydrogen Phosphate is used in agricultural fields?

Answer:

Potassium dihydrogen phosphate consists of Potassium and Phosphorous which helps in controlling the protein synthesis in plants that leads to healthy development of crops. It is used as fertilizer that feeds the plants with the nutrition they need to thrive in any crop condition.