Renewable Energy Questions on “Hydrogen Energy – 2”.
1. By what means can hydrogen be stored?
a) Physically and chemically
b) As atoms
c) As ions
d) As fuel cells
Answer: a
Clarification: Hydrogen can be stored either by physical or chemical means. Hydrogen atoms cannot be stored. Ions are intermediate species and exist only in reactions. Fuel cells are not used to store hydrogen.
2. How is hydrogen stored physically?
a) As atoms
b) By compressing hydrogen gas
c) In the form of hydrides
d) In the form of water
Answer: b
Clarification: For physical storage, the convention is to compress hydrogen gas and store it. Hydrogen atoms cannot be stored. Hydrogen is not stored as water. Besides, hydrides and water are not physical means of storing hydrogen.
3. How is hydrogen stored chemically?
a) As ions
b) By compressing hydrogen gas
c) In the form of hydrides
d) In the form of ice
Answer: c
Clarification: Conventionally, hydrogen molecules are converted to hydrides and stored. Ions are intermediate species and cannot be stored. Compression of hydrogen gas is a physical means of storage.
4. Hydrogen molecules are dissociated either _________ or _________ to form hydrides.
a) under sunlight or cold temperatures
b) by substitution or electrolysis
c) by electrolysis or heterolytically
d) homolytically or heterolytically
Answer: d
Clarification: Hydrogen molecules are dissociated either homolytically or heterolytically to form hydrides. This technique is a chemical means to store hydrogen. Electrolysis generates hydrogen. Substitution is a type of organic reaction.
5. Cryogenic adsorption is a physical means to store hydrogen.
a) True
b) False
Answer: a
Clarification: Cryogenic adsorption is a physical means to store hydrogen. After adsorbing hydrogen at low temperatures, it is stored as liquid hydrogen.
6. What are the main components of a fuel cell?
a) Anode, cathode, electrolyte
b) Anode, cathode, membrane and electrolyte (including fuel)
c) Anode, cathode
d) Anode, cathode, electrolyte and connecting wires
Answer: b
Clarification: Fuel cell is a device that converts chemical energy to electrical energy. It consists of the two electrodes namely, anode and cathode, a proton exchange membrane through with protons flow and the electrolyte in each chamber.
7. What is hydrogen compressor do to hydrogen?
a) Increases both pressure and volume
b) Decreases both pressure and volume
c) Increases pressure and decreases volume
d) Decreases pressure and increases volume
Answer: c
Clarification: Hydrogen compressor is a device that increases the pressure of hydrogen by reducing its volume. This results in the formation of compressed hydrogen or liquid hydrogen.
8. What is photocatalytic water splitting?
a) Splitting of water using catalyst and electricity
b) Splitting of water using electricity
c) Combining hydrogen and oxygen to form water
d) Splitting of water using light as catalyst
Answer: d
Clarification: Photocatalytic water splitting is an artificial photosynthesis process that is used to dissociate water into its constituents under the presence of natural or artificial light. It does not use chemical catalyst or electricity.
9. Which of the following uses hydrogen as fuel?
a) Vehicles
b) AA battery
c) AAA battery
d) Power plants
Answer: a
Clarification: Among the given options, vehicles use hydrogen as fuel. They are generally called hydrogen vehicles or hydrogen powered vehicles. These vehicles are powered using fuel cells.
10. Efficiency of water electrolysis is greater than the efficiency of steam reforming.
a) True
b) False
Answer: a
Clarification: Efficiency of water electrolysis is greater than the efficiency of steam reforming. However, electrolysis is not preferred because it is expensive.