18 Questions
What is the role of the anode in electrolysis?
Attracts the negative ion and undergoes oxidation
Which electrode in electrolysis is associated with reduction?
Cathode
What type of ions are attracted towards the cathode in electrolysis?
Positive ions (cations)
Which electrode reacts with the hydroxide ion in water electrolysis?
Anode
In the context of electrolysis, what does the cathode receive?
Extra electrons
Which electrode loses one electron to form a positive ion in electrolysis?
Anode
What is the main purpose of electrolysis in the context of hydrogen production?
To split water molecules into hydrogen and oxygen gas
Which of the following best describes the role of the cathode in the electrolysis of water?
The cathode attracts hydrogen ions and releases hydrogen gas
What happens at the anode during the electrolysis of water?
Oxygen ions combine with electrons to form oxygen gas
What is the primary function of the electric current in the electrolysis of water?
To provide the energy needed to break apart the water molecules
What is the role of the electrolyte solution in the electrolysis of water?
The electrolyte solution allows for the transport of ions and the creation of an electric field
What is the main advantage of using electrolysis to produce hydrogen compared to other methods?
Electrolysis can produce hydrogen without any byproducts
Which of the following electrolysis technologies uses a liquid alkali as the electrolyte?
Alkaline Electrolysis
Which electrolysis technology is known for its high energy efficiency but also has significantly higher capital costs?
Proton Exchange Membrane (PEM) Electrolysis
What is the primary advantage of High-pressure Alkali Membrane Electrolysis (HPMAE) technology?
It reduces the volume of the electrolyte needed to achieve the desired conductivity
Which of the following is NOT a challenge associated with electrolysis technologies for hydrogen production?
High energy efficiency
What factor should be considered when choosing the appropriate electrolysis technology for hydrogen production?
All of the above
What presents opportunities for innovation and improvement in the field of electrolysis and hydrogen production?
The challenges associated with electrolysis technologies
Study Notes
Electrolysis
Electrolysis is a chemical process used to decompose water into hydrogen and oxygen gases using electricity. It involves passing an electric current through a liquid or molten substance called an electrolyte, which dissociates into positively charged ions (cations) and negatively charged ions (anions). This process can occur when two metals with different electronegativities are placed in contact with each other and a direct electrical voltage is applied to them.
Electrodes
In electrolysis, two types of electrodes are typically used: the anode and the cathode. These electrodes play crucial roles in the overall process.
Anode
The negative ion (or anion) is attracted towards the positive electrode known as the anode, which undergoes oxidation because it loses one electron to form a positive ion. In this case, the hydroxide ion from the water molecule acts as the anion; hence, the anode reacts either with the hydroxide ion or with another species present in the solution to produce more positively charged ions.
Cathode
On the other hand, the positive ion (or cation) is attracted towards the negative electrode known as the cathode. Here, reduction occurs due to the gain of electrons by the cation, forming the neutral gas product. In the context of water electrolysis, the proton (H+) acts as the cation, and since all elements have a finite amount of electrons, the cathode receives these extra electrons.
To achieve successful electrolysis and generate useful products, the selection of appropriate electrodes plays a significant role. For instance, in chlorine alkali production, high surface area titanium or tantalum porous electrodes are often used for their excellent electrochemical performance and resistance to corrosion. Similarly, platinum was historically used in fuel cells, but has been replaced by more cost-effective alternatives like nickel catalysts.
Learn about the chemical process of electrolysis and the crucial roles played by the anode and cathode electrodes. Understand how anions and cations interact with the electrodes during electrolysis and the importance of selecting appropriate materials for successful electrolytic reactions.
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