Which of the following species would mostly likely be oxidized, if placed in a electrochemical cell with another species? With solid lithium as the reactant, any other solid can act as the product, and still give a positive , because the is the lowest value for lithium equation. Subtracting a negative number will give a positive value.
As a result, the equation, , will become inverted to make the solid lithium a reactant. Solid lithium will give electrons, and oxidize, to reduce other ions. Also, remember that electrons always flow from anode to cathode.
No knowledge about whether the cell is galvanic or electrolytic is needed, because the question assumes that the chemical reaction takes places. In this reaction, are gaining electrons to form , and the gaining of electrons only happens at the cathode. Therefore, is produced at the cathode. On the other hand, loses electrons to produce in the reaction, and the losing of the electrons only occur at the anode.
The question asks us which species is produced at the anode site of oxidation. Therefore, is produced at the anode. If you've found an issue with this question, please let us know.
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Possible Answers: Iron is reduced. Hydrogen will appear at the cathode, the negatively charged electrode, where electrons enter the water, and oxygen will appear at the anode, the positively charged electrode. The number of moles of hydrogen generated is twice the number of moles of oxygen, and both are proportional to the total electrical charge conducted by the solution. The number of electrons pushed through the water is twice the number of generated hydrogen molecules, and four times the number of generated oxygen molecules.
Johann Ritter, who went on to invent the first electrochemical cell, was one of the first people to discover the decomposition of water by electricity. Electrolysis of water : Device invented by Johann Wilhelm Ritter to develop the electrolysis of water. The amount of chemical change that occurs in electrolysis is stoichiometrically related to the amount of electrons that pass through the cell. The extent of chemical change that occurs in an electrolytic cell is stoichiometrically related to the number of moles of electrons that pass through the cell.
From the perspective of the voltage source and circuit outside the electrodes, the flow of electrons is generally described in terms of electrical current using the SI units of coulombs and amperes. It takes 96, coulombs to constitute a mole of electrons, a unit known as the faraday F.
This relation was first formulated by Michael Faraday in , in the form of two laws of electrolysis:. The equivalent weight of a substance is defined as the molar mass divided by the number of electrons required to oxidize or reduce each unit of the substance. A metallic object to be plated with copper is placed in a solution of CuSO 4.
What mass of copper will be deposited if a current of 0. Privacy Policy. Skip to main content. Search for:. Learning Objectives Predict the products of an electrolysis reaction. Key Takeaways Key Points The main components of an electrolytic cell are an electrolyte, DC current, and two electrodes. Key Terms electrolyte : A substance that, in solution or when molten, ionizes and conducts electricity. Electrolysis of Sodium Chloride Two commonly used methods of electrolysis involve molten sodium chloride and aqueous sodium chloride, which give different products.
Learning Objectives Predict the products of electrolysis of sodium chloride under molten and aqueous conditions. Key Takeaways Key Points Sodium metal and chlorine gas can be obtained with the electrolysis of molten sodium chloride.
Electrolysis of aqueous sodium chloride yields hydrogen and chlorine, with aqueous sodium hydroxide remaining in solution. Key Terms anode : The electrode of an electrochemical cell at which oxidation occurs.
A half equation is used to model the reaction that happens at an electrode during electrolysis. It shows what happens when ions gain or lose electrons. In half equations:.
Improve this answer. Designation of anode and cathode So labeling the anode and the cathode relies on an analogy between a voltaic cell and a photovoltaic cell as a source of electrical work. Direction of electron flow For the photovoltaic cell, maybe this picture helps: Before light hits the cell, anode and cathode are neither negative nor positive. Karsten Theis Karsten Theis The tricky part for the memorising is, anodes and cathodes flip the position , when the current is reversed, depending on if the cell is in the mode of electrolysis the cell is in the mode of providing current.
It does not necessarily mean it has more positive potential than the cathode , the negative electrode in power cell the minus electrode of the cell, providing electrons. It means the cathode is the negative electrode at electrolysis, accepting electrons from the external power source. Poutnik Poutnik Reduction is the gain of electrons. Oxidation is the loss of electrons. Huy Ngo Huy Ngo 3 3 silver badges 10 10 bronze badges. My description of which "gains" and "loses" might not be clear.
The actual question is, if the cathode indeed is the negative electrode? So the question is still: Why would electrons move towards the cathode, which is negative? I have added an extra diagram of simple electrolysis to explain this point a bit clearer - negative anions move towards the positive anode in order to deliver the excess electron. Positive cations move towards the negative cathode to receive electrons; that is what I meant by the cathode "supplying electrons".
If this is a electrolyser, then yeah, cathode, is negative. But this "negative" is different from the negative in cell case. This "negative" means, the negative end of electricity supply is connected to cathode, and cathode receiving electron from that. The material that loses electrons in one direction gains electrons coming from the other side. Mitchell Mitchell 1, 6 6 silver badges 13 13 bronze badges.
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