Engineering Questions with Answers - Multiple Choice Questions
Chemical Industry MCQ’s – Inorganic Chemical – Calcium Phosphate
1 - Question
Super phosphate grade of calcium phosphate is formed by reacting with which of the following acid?
a) H2SO4
b) HCl
c) H3PO4
d) HNO3
View Answer
Explanation: Superphosphate grade of calcium phosphate is produced by the reaction of phosphate rock with sulfuric acid, H2SO4.
2 - Question
What is the percentage of P2O5 present in triple super phosphate?
a) 16-20%
b) 42-50%
c) 30-35%
d) 62-70%
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Explanation: Super phosphate contains 16-20% P2O5 whereas triple super phosphate contains 42-50% P2O5. These are 2 distinct grades of calcium phosphate.
3 - Question
What is the chemical formula of super phosphate?
a) CaH4 (PO4)2
b) Ca3 (PO4)2
c) CaH4 (PO4)2∙CaSO4
d) (Ca3 (PO4)2)3∙CaF2
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Explanation: Chemical formula of super phosphate formed by reaction of phosphate rock with sulfuric acid containing 16-20% P2O5 is CaH4 (PO4)2∙CaSO4.
4 - Question
What is the chemical formula of triple super phosphate?
a) (Ca3 (PO4)2)3∙CaF2
b) CaH4 (PO4)2
c) Ca3 (PO4)2
d) CaH4 (PO4)2∙CaSO4
View Answer
Explanation: Chemical formula of triple super phosphate formed by reaction of phosphate rock with phosphoric acid containing 42-50% P2O5 is CaH4(PO4)2.
5 - Question
What is the reaction time of triple super phosphate formation?
a) 15-20 min
b) 5-6 min
c) 5-15 min
d) 20-30 min
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Explanation: Acid is mixed with ground rock in a continuous mixer, which is sent into continuous belt reactor where reaction completes in 15-20 min.
6 - Question
At which stage ammonia is added if ammonium phosphate is required in manufacture of triple super phosphate?
a) Continuous belt reactor
b) Rotary dryer
c) Rotary granulator
d) Feeder
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Explanation: Ammonia along with water is added to feed from continuous belt reactor (including recycle steam) in rotary granulator if ammonium phosphate is required.