Unit Processes Multiple Choice Questions on “Catalyst”.
1. What are the commonly used catalysts for the Fischer Tropsch synthesis?
a) Nickel
b) Cobalt
c) Iron
d) All of the mentioned
Answer: d
Clarification: Nickel, cobalt, and iron catalysts are commonly used for the Fischer Tropsch synthesis.
2. Cobalt catalyst is used when which type of products are desired?
a) Solid
b) Liquid
c) Vapour
d) None of the mentioned
Answer: b
Clarification: Cobalt catalysts are preferable to nickel when greater yields of liquid products are desired.
3. Complete the following reaction: 3Fe2C + 4H20 —–> 2_____ + 3C + 4H2.
a) Fe3O5
b) Fe3O4
c) Fe3O4
d) Fe2O4
Answer: c
Clarification: Carbon forming reaction is: 3Fe2C + 4H20 —–> 2Fe3O4 + 3C + 4H2.
4. Iron catalysts operate over a considerably wider temperature range.
a) True
b) False
Answer: a
Clarification: Iron catalysts operate over a considerably wider temperature range, 200-350°C, than do cobalt catalysts. The space velocity of operation is almost directly proportional to the pressure.
5. What happens to the yield of heavier products as temperature increases?
a) Increases
b) Remains same
c) Decreases
d) None of the mentioned
Answer: c
Clarification: The gasoline yield increases as the temperature increases, while the yield of heavier products decreases. A similar shift of products to lighter material occurs when the alkali content of the catalyst is decreased.
6. Which catalyst is prepared by precipitation from a nitrate solution with potassium carbonate?
a) Iron
b) Zinc
c) Nickel
d) Iron
Answer: c
Clarification: Nickel catalysts have been prepared by precipitation from a nitrate solution with potassium carbonate in the presence of thoria and kieselguhr in the proportions 100Ni: 18ThO2: 100 kieselguhr.
7. By which process Iron can be prepared?
a) From magnetite
b) Iron oxide
c) Oxidation of metals
d) All of the mentioned
Answer: d
Clarification: Iron catalysts may be prepared for commercial applications by precipitation from solution, from magnetite (Fe3O4) ore, or from magnetite obtained by fusion of iron oxides, or by oxidation of metallic iron with steam.
8. The magnetite catalysts are reduced to what?
a) Metallic iron
b) Metallic copper
c) Metallic zinc
d) All of the mentioned
Answer: a
Clarification: The magnetite catalysts are generally reduced to metallic iron with pure hydrogen at space velocities of 2,000 hr’-1 and at 400-500°C.
9. What are the factors that affects product distribution?
a) Temperature
b) Alkali
c) Both temperature and alkali
d) None of the mentioned
Answer: c
Clarification: The two main factors affecting product distribution are temperature and alkali.