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Ch.20 - Electrochemistry
Tro - Chemistry: A Molecular Approach 6th Edition
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217Not the one you use?Change textbook
All textbooksTro 6th EditionCh.20 - ElectrochemistryProblem 100a
Chapter 20, Problem 100a

Write equations for the half-reactions that occur at the anode and cathode for the electrolysis of each aqueous solution. a. Ni(NO3)2(aq)

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Step 1: Identify the ions present in the solution. In this case, the solution of Ni(NO3)2(aq) will dissociate into Ni2+ ions and NO3- ions.
Step 2: Determine the possible reactions at the anode and cathode. The anode is where oxidation occurs, and the cathode is where reduction occurs. In an aqueous solution, water can also be oxidized or reduced, producing O2 and H2 respectively.
Step 3: Write the half-reactions. For the anode (oxidation), the possible reactions are the oxidation of Ni2+ to Ni or the oxidation of water to O2. For the cathode (reduction), the possible reactions are the reduction of Ni2+ to Ni or the reduction of water to H2.
Step 4: Determine the most likely reactions based on the standard reduction potentials. The reaction with the higher reduction potential is more likely to occur at the cathode, and the reaction with the lower reduction potential is more likely to occur at the anode.
Step 5: Write the final half-reactions. The final half-reactions will depend on the standard reduction potentials of the possible reactions. Remember to balance the half-reactions by adding electrons to the appropriate side.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Electrolysis

Electrolysis is a chemical process that uses electrical energy to drive a non-spontaneous reaction. In this process, an electric current is passed through an electrolyte, causing the decomposition of the compound into its constituent elements or ions. The reactions occur at two electrodes: the anode (oxidation) and the cathode (reduction), where different half-reactions take place.
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Half-Reactions

Half-reactions are the individual oxidation or reduction reactions that occur at the electrodes during electrolysis. Each half-reaction shows the transfer of electrons and the change in oxidation states of the species involved. For example, at the anode, a species may lose electrons (oxidation), while at the cathode, another species gains electrons (reduction).

Electrolyte Solutions

Electrolyte solutions contain ions that can conduct electricity, allowing electrolysis to occur. In the case of Ni(NO3)2(aq), the solution dissociates into nickel ions (Ni²⁺) and nitrate ions (NO3⁻). The specific ions present in the solution will determine the products formed at the electrodes during electrolysis, influencing the half-reactions that need to be written.
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