Download Chapter 17 Electrochemistry multiple choice

Chapter 17 Electrochemistry multiple choice
A 97-37. Which of the following statements is true according to the potentials below?
Eº (volts)
Ag+ + e  Ag
0.800
Pb2+ + 2e  Pb -0.126
V2+ + 2e-  V
-1.18
A. Ag metal will reduce Pb2+ ions.
C. Pb metal will reduce Ag+ ions.
B. Ag metal will reduce V2+ ions.
D. Pb metal will reduce V2+ ions.
H 96-36. Chlorine is produced by the electrolysis of aqueous sodium chloride solutions according
to the equation:
2Cl-  Cl2 + 2e-.
Which one of the following statements about the process is correct?
A. Chlorine is formed at both electrodes.
B. Chlorine is formed at one electrode and sodium metal is formed at the other end.
C. Chlorine is formed at one electrode and hydrogen gas is formed at the other.
D. Chlorine is formed at one electrode and hydrogen gas is formed at the other.
A 95-36. The equation below represents a reaction which occurs in an electrochemical cell.
Mn(s) + Co2+(aq)  Co(s) + Mn2+(aq)
Which one of the following statements is true?
A. Positive ions move towards the Mn electrode through the solution.
B. elecrons move toward the Mn electrode through the solution.
C. Negative ions move toward the Co electrode through the solution.
D. Electrons move toward the Co electrode through the external circuit.
A 95-37. The electrolysis of aqueous NaCl can be represented by the equation:
2Cl-(aq) + 2H2O(l)  Cl2(g) + H2(g) + 2OH-(aq)
Which statement about this process is true?
A. Chlorine is formed at the anode.
B. The anode compartment will turn pink if phenolphthalein is added.
C. Twice as much electricity is needed to produce the hydrogen gas and hydroxide
ions as is needed to produce the chlorine gas.
D. This reaction could be used to produce electrical energy.
A 93-36.
Al3+ + 3e-  Al
2Cl-  Cl2 + 2e-
Mg2+ + 2e-  Mg
2H2O  4H+ + O2 + 4e-
The equation above represent the electrolytic production of the elements: Al, Mg, Cl 2
and O2. The production of one mole of which element will require the greatest
quantity of electricity?
A. Al
B. Mg
C. Cl2
D. O2
A 93-37. Which statement is true when an aqueous solution of CuCl2 is electrolysed with a direct
current?
A. Electrons enter the cell at the anode.
B. Cu2+ ions migrate toward the cathode.
C. The current is carried through the solutions by electrons.
D. The amount of copper metal produced is one half the amount mole of chlorine
gas.
A 92-37. The same quantity of electricity is passed through two solutions, one containing a salt
of the unknown metal, X, and the other containing a salt of unknown metal, Y. If
0.020 mole of X is produced at the cathode of one cell, and 0.040 mole of Y is
produced at the cathode of the other, which of the following conclusions can be
drawn?
I. The ions of X and Y are positively charged.
II. The X ion has a plus two charge.
III. The charge on the X ion is double that on the Y ion.
IV. The Y ion has a plus one charge.
A. I only
B. I and III only C. II and IV only
D. I, III, IV only
A 91-37. Which one of the following processes occurs during the electrolsis of an aqueous
sodium chloride solution?
A. Na+ gains electrons at the cathode.
B. Cl atoms gain electrons at the cathode.
C. Cl- lose electrons at the anode.
D. Water is reduced at the anode.
G 93-32. Given the standard electrode potentials:
Cr3+(aq) + 3e  Cr(s)
Pb2+(aq) + 2e  Pb(s)
Eº = -0.74 volt
Eº = -0.13 volt
What is the standard cell potential, Eºcell , for the reaction shown below?
2Cr(s) + 3Pb2+(aq)  2Cr3+(aq) + 3Pb(s)
A. -0.87 volt B. 1.09 volt
C. 0.61 volt
D. -1.87 volt
G 92-32. An electrolysis cell connected in series with one which deposits 12 grams of
magnesium would, during the same time interval, deposit
A. 23 grams of sodium.
B. 27 grams of aluminium.
C. 32 grams of oxygen.
D. 4 grams of hydrogen.
G 92-34. The following are standard half-cell reduction potentials:
Cu2+ + 2e  Cu
Ni2+ + 2e  Ni
;
;
Eº = +0.34 volt
Eº = -0.25 volt
An electrochemical cell consisting of a copper-copper(II) nitrate solution half-cell and a
nickel-nickel(II) nitrate solution half-cell, joined by a salt bridge, has a
A. cell potential of +0.59 volt, with electron flow from Ni to Cu.
B. cell potential of +0.09 volt, with electron flow from Ni to Cu.
C. cell potential of +0.59 volt, with electron flow from Cu to Ni.
D. cell potential of -0.59 volt, with electron flow from Ni to Cu.
G 92-35. When a direct current of electricity is conducted by an aqueous solution of an
electrolyte, which one of the following statements is FALSE?
A. The movement of ions account for the current flow through the solution.
B. During electrolysis, the solution remains electrically neutral.
C. Electrons flow from the current source toward the solution at one electrode, and an
equal number of electrons flows away from the solution at the other electrode.
D. The number of positive ions moving toward one electrode is always equal to the
number of negative ions moving toward the other electrode.
G 91-32. To which electrode are the potassium ions attracted during the electrolsis of molten
potassium bromide?
A. The anode which has a positive charge
B. The anode which has a negative charge.
C. the cathode which has a positive charge.
D. The cathode which has a negative charge.