Unit Processes Multiple Choice Questions on “Esters of Inorganic acids”.
1. Which of the following is an ester of inorganic acid?
a) Sulfuric acid
b) Phosphoric acid
c) Silicic acid
d) All of the mentioned
Answer: d
Clarification: The commercially important esters of inorganic acids are those of nitric, sulfuric, phosphoric, and silicic acids. The nitrates of glycerol and cellulose are among the oldest of synthetic chemical products. They are prepared by the direct esterification of the alcohol by nitric acid.
2. The nitration is carried out in only homogeneous phase.
a) True
b) False
Answer: b
Clarification: The nitration may be carried out in either a homogeneous or a heterogeneous reaction system.
3. What is a mixed acid?
a) HCl+ HNO3
b) H2SO4+HCl
c) H2SO4+ HNO3
d) All of the mentioned
Answer: c
Clarification: A mixed acid, which is a mixture of nitric and sulfuric acids and may contain water or sulphur trioxide, the concentrations of these being accurately adjusted to give the desired degree of nitration.
4. What is done to avoid polymerization of the hydrocarbons?
a) Low temperature
b) High heat
c) Catalyst
d) High temperature
Answer: a
Clarification: To avoid polymerization and isomerization of the hydrocarbons, the temperature is kept relatively low, usually from 0-40°C.
5. Complete the following reaction: C2H5OH + HNO3 ——> C2H5ONO2 + H2O.
a) C2H5ONO3
b) C2H5ONH2
c) C2H5ONO2
d) C2H5NO2
Answer: c
Clarification: C2H5OH + HNO3 ——> C2H5ONO2.
6. “Care must be taken to achieve uniformity of nitration”.
a) True
b) False.
Answer: a
Clarification: In carrying out the reaction, care must be taken to achieve uniformity of nitration, since the value of the product is largely dependent on its approach to homogeneity.
7. What is the use of monosulphates?
a) Drying agent
b) Detergent
c) Catalyst
d) All of the mentioned
Answer: b
Clarification: The monosulfates, have a wide range of uses as detergents and wetting agents.
8. Phosphates are prepared by the reaction of what?
a) Phosphorus pentachloride
b) Phosphorus oxychloride
c) Phosphorus pentachloride & oxychloride
d) None of the mentioned
Answer: c
Clarification: Phosphates are prepared by the reaction of phosphorus pentachloride or phosphorus oxychloride with the appropriate alcohol or phenol.
9. What is the formula of sulphur analogue of phosphorus oxychloride?
a) PSCl3
b) PSCl5
c) PSCl2
d) PCl2S
Answer: a
Clarification: If the sulphur analogue of phosphorus oxychloride, PSCl3, is caused to react with an alcohol, or its sulphur analogue, a mercaptan, the corresponding thioester is obtained.
10. By adjusting the strength of the sulfuric acid solution, the absorption may be made selective.
a) True
b) False
Answer: a
Clarification: By adjusting the strength of the sulfuric acid solution, the absorption may be made selective, so that certain unsaturated hydrocarbons may be removed from a mixture of olefins.