Engineering Questions with Answers - Multiple Choice Questions
Chemical Industry MCQ’s – Inorganic Chemical – Sodium Phosphate
1 - Question
Which one of the following is the structure of hexa Meta phosphate? X represents monovalent alkali metal.
a) X5P3O10
b) (XPO3)6
c) PO4-3
d) X4P2O7∙YH2 O
View Answer
Explanation: The structure of meta phosphate is PO3–, on combining X and PO3– we get XPO3. Hence hexa Meta phosphate structure is (XPO3)6.
2 - Question
What is the chemical formula for sodium Tri polyphosphate?
a) Na4P2O7
b) Na3PO4
c) NaPO3
d) Na5P3O10
View Answer
Explanation: The chemical structure of poly phosphate is X5P3O10. Hence the chemical formula for sodium tri polyphosphate is Na5P3O10 which is formed by the combination of 1 mole of monosodium to 2 moles of disodium phosphate.
3 - Question
What is the molecular weight of Na5P3O10?
a) 368
b) 363
c) 360
d) 365
View Answer
Explanation: The atomic weights of sodium, phosphorous, oxygen are 23, 31, and 16 respectively. Hence the total molecular weight is (23*5) + (31*3) + (16*10) = 368.
4 - Question
What ratio of Na2O/P2O5 is required to form of 1 mole of monosodium to 2 moles of disodium phosphate?
a) 1.87
b) 1.62
c) 1.67
d) 1.82
View Answer
Explanation: Soda ash solution and concentrated H3PO4 are diluted in a batch mixing tank. A 1.67 ratio of Na2O/P2O5 is required to form of 1 mole of monosodium to 2 moles of disodium phosphate.
5 - Question
Which type of rotary dryer is used in manufacture of sodium tri polyphosphate?
a) Rotary drum dryer
b) Indirect fired and cooled rotary dryer
c) Rotary vacuum dryers
d) Direct rotary dryers
View Answer
Explanation: The sodium tri polyphosphate solution is filtered, dried, cooled and annealed along the length of the indirect fired and cooled rotary drier.