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).
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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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Electrolytes and Strong Acids