Unit Processes Multiple Choice Questions on “Classification of hydrogenation catalyst”.
1. Hydrogenation involve the saturation of which type of linkage?
a) Carbon-carbon
b) Carboxyl group
d) Hydroxyl group
d) All of the mentioned
Answer: d
Clarification: Hydrogenation may involve the saturation of a carbon-to-carbon linkage or the reduction of carbonyl or carboxyl or hydroxyl groups and may even involve the breaking of carbon-to-carbon linkages, as in the hydrogenation of coals and mineral oils.
2. Which catalyst carry hydrogenation to the maximum?
a) Mild Catalyst
b) Vigorous catalyst
c) Both mild and vigorous catalyst
d) None of the mentioned
Answer: b
Clarification: Vigorous Hydrogenation Catalysts, these catalysts are usually characterized by the fact that they carry the hydrogenation to the greatest extent possible, so that the maximum addition of hydrogen to compound occurs under the particular operating conditions.
3. Cracking tendencies are associated with which type of hydrogenation catalysts?
a) Vigorous
b) Mild
c) Slow
d) All of the mentioned
Answer: a
Clarification: Cracking tendencies are usually associated with these vigorous hydrogenation catalysts, although through control of the variables of temperature and pressure, the cracking reactions can usually be suppressed.
4. Which of the following is a vigorous catalyst?
a) Nickel
b) Cobalt
c) Molybdenum
d) All of the mentioned
Answer: d
Clarification: Common catalysts belonging to this class usually consist of the nickel, cobalt, or iron type, as well as molybdenum and tungsten oxides or sulphides.
5. Mild hydrogenation are slower than vigorous hydrogenation.
a) True
b) False
Answer: b
Clarification: The term mild should not be confused with activity. These catalysts will effect hydrogenations just as rapidly as the vigorous hydrogenation types, but they are able to carry out only one step at a time in a hydrogenation, or at least they do not permit the reaction to proceed to the hydrocarbon stage.
6. Which of the following is mild hydrogenation catalyst?
a) Nickel
b) Iron
c) Zinc oxide
d) All of the mentioned
Answer: c
Clarification: The large number of catalysts developed for the direct synthesis of methanol from water gas belong to this, class, and they usually contain copper, zinc oxide, chromium oxide, and manganese oxide and may include some of the rarer elements as promoters.
7. Which of the following is a Nobel-metal catalyst?
a) Zinc oxide
b) Platinum
c) Chromium
d) All of the mentioned
Answer: b
Clarification: In addition, the noble-metal catalysts such as platinum or palladium or their oxides belong to mild hydrogenation catalyst class.
8. Vanadium oxide is a sulphur-resistant catalyst for hydrogenating.
a) True
b) False
Answer: a
Clarification: Vanadium oxide, which is widely used as an oxidation catalyst, is reported to be a sulphur-resistant catalyst for hydrogenating unsaturated hydrocarbons, but temperatures in the range of 400°C are required.
9. What is higher-alcohol catalysts consists of?
a) Sodium
b) Calcium
c) Barium carbonates
d) All of the mentioned
Answer: d
Clarification: Higher-alcohol catalysts are usually of the mild hydrogenating type but contain some more alkaline materials, such as sodium, calcium, or barium carbonates or aluminium or magnesium oxides.
10. What are the hydrogenation reactions catalysed by molybdenum compounds?
a) Reduction in unsaturated
b) Cleavage of C-C
c) Dehydroisomerization
d) All of the mentioned
Answer: d
Clarification: The hydrogenation reactions catalysed by molybdenum compounds are (1) reduction of unsaturated, (2) cleavage of carbon-to-carbon, carbon to-sulphur, carbon-to-oxygen, and carbon-to-nitrogen linkages, (3) reduction of nitro compounds to amines, and (4) dehydroisomerization.