250+ TOP MCQs on Inorganic Chemical – Sodium Phosphate and Answers

Chemical Industry Interview Questions on “Inorganic Chemical – Sodium Phosphate”.

1. 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

Answer: b
Clarification: The structure of meta phosphate is PO₃^–, on combining X and PO₃^– we get XPO₃. Hence hexa Meta phosphate structure is (XPO₃)₆.

2. What is the chemical formula for sodium Tri polyphosphate?
a) Na₄P₂O₇
b) Na₃PO₄
c) NaPO₃
d) Na₅P₃O₁₀

Answer: d
Clarification: 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. What is the molecular weight of Na₅P₃O₁₀?
a) 368
b) 363
c) 360
d) 365

Answer: a
Clarification: 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. 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

Answer: c
Clarification: 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. 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

Answer: b
Clarification: The sodium tri polyphosphate solution is filtered, dried, cooled and annealed along the length of the indirect fired and cooled rotary drier.