Engineering Questions with Answers - Multiple Choice Questions
Unit Processes MCQ’s – Catalytic Hydrogenation
1 - Question
Complete the following reaction: R-CC-R’ + H2 —–> _______
a) R-CH-CH-R’
b) R-CH2-CH3
c) R-CH2-CH2-R’
d) All of the mentioned
View Answer
Explanation: The reaction is hydrogenation reaction and is as follows: R-CC-R’ + H2 —–>R-CH2-CH2-R.
2 - Question
How is selective hydrogenation achieved?
a) Heat supplied
b) Catalyst used
c) Reactants
d) Products
View Answer
Explanation: Selective hydrogenation of the acetylene to ethylene is accomplished by passing the mixture, which also contains 10-35 per cent of hydrogen, over a catalyst at a temperature ranging from 200-315°C and at pressures of 45-155 psig.
3 - Question
In presence of what, the compounds undergo catalytic hydrogenation?
a) Nickel
b) Platinum
c) Palladium
d) All of the mentioned
View Answer
Explanation: Compounds of this class readily undergo catalytic hydrogenation, usually in the presence of a nickel or nickel-containing catalyst and sometimes with platinum or palladium catalysts.
4 - Question
Fill in the blank: _____ molecular weight olefins are generally hydrogenated in the liquid phase.
a) Lower
b) Higher
c) Moderate
d) None of the mentioned
View Answer
Explanation: Higher-molecular-weight olefins are generally hydrogenated in the liquid phase unless their volatility is sufficient at the temperature of hydrogenation (150-200°C), in which case the reaction may be conducted in the vapour phase.
5 - Question
What are the properties of Polybutadiene?
a) Thermoplastics
b) Oil resistance
c) Tensile strength
d) All of the mentioned
View Answer
Explanation: Polybutadiene may be hydrogenated over nickel catalyst at 260°C to hydrorubbers (Hydropol) of various degrees of unsaturation. These rubbers have outstanding properties as thermoplastics, especially as to low temperature properties, oil resistance, and tensile strength.
6 - Question
Diolefins undergo catalytic hydrogenation to produce which type of hydrocarbon?
a) Saturated
b) Unsaturated
c) Aromatic
d) Azo
View Answer
Explanation: Diolefins, compounds containing such linkages undergo catalytic hydrogenation to give the corresponding saturated hydrocarbons.
7 - Question
Aromatic require what temperature to achieve complete hydrogenation?
a) 130°C
b) 150°C
c) 18°C0
d) 200°C
View Answer
Explanation: Aromatics, such compounds generally require temperatures above 180°C for complete hydrogenation over nickel catalysts
8 - Question
The catalytic reduction of aromatics require on Liquid phase.
a) True
b) False
View Answer
Explanation: The catalytic reduction of aromatics may be carried out either in the vapour phase at atmospheric pressure or in the liquid phase at hydrogen pressures or 100-200 atm.
9 - Question
Olefins rapidly hydrogenate at what temperature?
a) Lower
b) Moderate
c) Higher
d) None of the mentioned
View Answer
Explanation: Olefins rapidly hydrogenate at a much lower temperature, such a difference in reactivity is the basis of an analytical procedure for differentiating between olefinic and aromatic bonds.
10 - Question
Which is the most widely used catalyst for hydrogenation if aromatics?
a) Cadmium
b) Zinc
c) Nickel
d) Iron
View Answer
Explanation: Nickel is the most widely used catalyst for hydrogenating aromatic nuclei, other catalysts such as platinum oxide and rhodium also are useful.
11 - Question
Aldehydes are reduced more rapidly than ketones.
a) True
b) False
View Answer
Explanation: Aldehydes are reduced more rapidly than ketones, although there are numerous examples in which both aldehydes and ketones undergo reduction at room temperature and at only a few atmospheres of hydrogen pressure in the presence of platinum or palladium catalysts.
12 - Question
Heterocyclic Compounds undergo which type of hydrogenation?
a) Partial hydrogenation
b) Catalytic hydrogenation
c) Selective hydrogenation
d) Hydrogenolysis
View Answer
Explanation: Heterocyclic Compounds, such materials undergo catalytic hydrogenation to yield the corresponding saturated derivatives.