Unit Processes Multiple Choice Questions on “Mixed Acids for Nitrations”.
1. Why is there a need to have one of the reactant in excess?
a) To achieve equilibrium faster
b) Satisfying the stoichiometric requirement
c) Stable reaction
d) All of the mentioned
Answer: d
Clarification: One of the reactant is usually present in excess in order to maintain reasonably fast over-all reaction rates and to satisfy the stoichiometric requirements of the nitration reaction.
2. What does D.V.S stand for?
a) Denitration of Sulphuric acid
b) Dehydrating value of sulphuric acid
c) Decomposition of Sulphuric acid
d) None of the mentioned
Answer: b
Clarification: D.V.S. (dehydrating value of sulfuric acid) and is used for mixed-acid calculations.
3. What do we denote Nitric ratio as?
a) N
b) n
c) R
d) r
Answer: c
Clarification: Nitric ratio is denoted by ‘R’ and it is the ratio of the weights of 100 per cent HN03 to weight of material being nitrated.
4. What do you mean by Nitric ratio?
a) Ratio of wt of 100% HNO3 / wt of materials being nitrated
b) Ratio of wt of 100% HNO3/ wt of 100% H2SO4
c) Ratio of wt of 100% H2SO4/ wt of materials being nitrated
d) Ratio of wt of 100% H2SO4/ wt of 100% HNO3
Answer: a
Clarification: Nitric ratio is denoted by ‘R’ and it is the ratio of the weights of 100 per cent HN03 to weight of material being nitrated.
5. What is NO2+ called?
a) Nitryl ion
b) Nitronium ion
c) Both of the mentioned
d) None of the mentioned
Answer: c
Clarification: The NO2+ is called nitrly or nitronium ion, it is called an ion because it contains a charge on it.
6. To calculate D.V.S. from the mixed-acid analysis the formula is, D.V.S ___________
a) S/(EW/R+W)
b) S/(ES/R+W)
c) S / (ER/ R+W)
d) S / (EN / R+W)
Answer: d
Clarification: For calculating the DVS Value the following formula is used : S / (EN / R+W) , Where: S = percent actual H2SO4,
N = per cent actual HNO3
W = per cent water
E = water equivalent of material to be nitrated and
R = nitric ratio.
7. Which of the following is the correct formula?
a) R= N/X
b) EN/R = EX
c) X= N/R
d) All of the mentioned
Answer: d
Clarification: The formula for nitric acid (R) is R= N/X which can be rearranged to get the other formulae.
8. What happens while decreasing the D.V.S value?
a) Increase in stability
b) Decrease in stability
c) Doesn’t affect the stability
d) Both increase and decrease stability
Answer: b
Clarification: It is found experimentally that increasing D.V.S. favours high stability of the nitrator charge, while decreasing the D.V.S results in lowering stability.
9. Why is keeping the D.V.S ratio high, a stability factor?
a) Tends to complete nitration and esterification reaction
b) Accumulation of incompletely nitrated material
c) All of the mentioned
d) None of the mentioned
Answer: a
Clarification: Since increasing D.V.S. tends to drive the nitration or esterification farther toward completion, whereas lower D.V.S. would permit accumulation of incompletely nitrated material, along with increased dilution, and this would be favourable to oxidation reactions.
10. Complete the reaction? C6H6 + NO2-OH ——–> _______ + H2O.
a) C6H5-NH4
b) C6H5-NH3
c) C6H5-NO2
d) C6H5-OH
Answer: c
Clarification: The reaction is used for the production of Nitrobenzene: C6H6 + NO2-OH ——–> C6H5-NO2 + H2O.