CHEM 1050 Lecture Notes - Lecture 4: Aqueous Solution, Sodium Chloride, Spontaneous Process

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periwinkleferret158

22 Sep 2015

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Notes: reduction rxn occurs at electrode (cathode) attached to. [positive or negative] terminal of the battery: oxidation rxn occurs at electrode (anode) attached to. [positive or negative] terminal of the battery. the the. The big difference with electrolysis is that we know the reactants (but have to predict the products)! One form of electrolysis involves a molten salt. Molten means the salt is heated to the point where the solid is converted to a liquid state. Ref: ebbing and gammon, general chemistry, 10th ed. , 2013, p. 807. Problem 1: which of the following are true for an electrolytic cell: g < 0, none of the above is true. 2h2o(l) + 2e h2(g) + 2oh (aq), e = 0. 83v (reduction at cathode) electrolytic cell. Predict the substance formed at the anode: i2(l, br2(l, ca(l, k(l) B k > 1: e cell > 0, all of the above are true.

Related Questions

What is an electrolytic cell? (b) The negative terminal of a voltage source is connected to an electrode of an electrolytic cell. Is the electrode the anode or the cathode of the cell? Explain. (c) The electrolysis of water is often done with a small amount of sulfuric acid added to the water. What is the role of the sulfuric acid? (d) Why are active metals such as Al obtained by electrolysis using molten salts rather than aqueous solutions?

orchidmule244

Magnesium is produced commercially by electrolysis from a molten salt using a cell similar to the one shown here. (a) What salt is used as the electrolyte? (b) Which electrode is the anode, and which one is the cathode? (c) Write the overall cell reaction and individual half-reactions. (d) What precautions would need to be taken with respect to the magnesium formed? [Section 20.9]

One Class Solution:- a) Magnesium chloride must be heated until it is molten before it will conduct electricity. Electrolysis separates the molten ionic compound into its elements.

b, c)Mg²⁺ + 2e-→Mg (magnesium metal at the (-) cathode). Steel electrodes.

2Cl^- - 2e- →Cl₂ (chlorine gas at the (+) anode)- Carbon electrode.

Mg is an active metal- >It must be separated from the Cl₂(g) that is also formed by electrolysis or MgCl₂ will spontaneously reformed.

ochrealpaca762

Mc 12/20

Electrolysis of Molten Salts Electrolytic cells use electricity to cause a nonspontaneous redox reaction to occur. An electrolytic cell is constructed using the following components: a power source, such as a battery, the substance that will undergo electrolysis, and two inert electrodes (usually platinum), which serve as the electrical connection between the power source and the substance undergoing electrolysis. When electricity is applied to a molten binary salt during electrolysis, the cation will be reduced and the anion will be oxidized. If more than one cation is present, only the one with highest reduction potential will be reduced. Similarly, if more than one anion is present, only the one with the highest oxidation potential will be oxidized. Part A What substance is produced at the cathode during the electrolysis of molten calcium bromide, CaBr2? Assume standard conditions. Express your answer as a chemical formula. Hints SubmitMy AnswersGive Up Part B What substance is produced at the anode during the electrolysis of molten calcium bromide, CaBr2? Assume standard conditions. Express your answer as a chemical formula. Hints SubmitMy AnswersGive Up Part C What substance is produced at the cathode during the electrolysis of a mixture of molten calcium bromide, CaBr2(l), and molten magnesium iodide, MgI2(l)? Assume standard conditions. Express your answer as a chemical formula. Hints SubmitMy AnswersGive Up Part D What substance is produced at the anode during the electrolysis of a mixture of molten calcium bromide, CaBr2(l), and molten magnesium iodide, MgI2(l)? Assume standard conditions. Express your answer as a chemical formula. Hints SubmitMy AnswersGive Up

CHEM 1050 Lecture Notes - Lecture 4: Aqueous Solution, Sodium Chloride, Spontaneous Process

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