Phosphate rocks - in the form of Ca3(PO4)2 are soluble in water - True or False?
The correct option is B False
Phosphorus is one of the most important nutrients for plants and in general chemical fertilizers are used to provide vital nutrients like N, P and K. A combination that provides all the three nutrients are generally called "NPK" fertilizers. So there are many such combinations.
To answer the question Ca3(PO4)2 is insoluble in water. To make it soluble, phosphate rocks are treated with concentrated H2SO4
Ca3(PO4)2+2H2SO4→Ca(H2PO4)2+2CaSO4
Ca(H2PO4)2 is soluble in water.
Although the above reaction is correct, a more appropriate version of synthesizing superphosphate is accomplished by using fluorapatite instead of the Calcium phosphate. In that case, we get superphosphate if fluorapatite Ca5(PO4)3 F is leached with concentrated sulphuric acid. This process also produces some insoluble CaSO4 which is of no nutritional benefit to the plants. Instead, if concentrated Phosphoric acid is used to leach fluorapatite, we get triple superphosphate!
The reaction is as follows:
Ca5(PO4)3F+7H3PO4→5Ca(H2PO4)2+HF
Ca(H2PO4)2 is soluble in water. The product obtained in the above reaction is called triple super-phosphate
Phosphorus is one of the most important nutrients for plants and in general chemical fertilizers are used to provide vital nutrients like N, P and K. A combination that provides all the three nutrients are generally called "NPK" fertilizers. So there are many such combinations.
To answer the question Ca3(PO4)2 is insoluble in water. To make it soluble, phosphate rocks are treated with concentrated H2SO4
Ca3(PO4)2+2H2SO4→Ca(H2PO4)2+2CaSO4
Ca(H2PO4)2 is soluble in water.
Although the above reaction is correct, a more appropriate version of synthesizing superphosphate is accomplished by using fluorapatite instead of the Calcium phosphate. In that case, we get superphosphate if fluorapatite Ca5(PO4)3 F is leached with concentrated sulphuric acid. This process also produces some insoluble CaSO4 which is of no nutritional benefit to the plants. Instead, if concentrated Phosphoric acid is used to leach fluorapatite, we get triple superphosphate!
The reaction is as follows:
Ca5(PO4)3F+7H3PO4→5Ca(H2PO4)2+HF
Ca(H2PO4)2 is soluble in water. The product obtained in the above reaction is called triple super-phosphate
