Analytical Chemistry: Fundamentals to Electrochemistry

An electrode with a fixed potential is the:

• reference electrode.

• indicator electrode.

• cathode.

• anode.

• working electrode.

___ is a set of techniques that observes the relationship between current and voltage during an electrochemical process.

• Electrophoresis

• Voltammetry

• Coulometry

• Amperometry

• Electrogravimetric analysis

For the line notation below, which is NOT true?

Fe(s)| Fe2+ (aq, 1 M) || Cu2+ (aq, 1 M) | Cu (s)

• || represents the salt bridge.

• Cu is the anode.

• Fe is the anode.

• 1 M Cu2+ is the electrolyte concentration and species for the copper electrode.

• 1 M Fe2+ is the electrolyte concentration and species for the iron electrode.

Which of the following is NOT true for galvanic cells?

• Galvanic cells are composed of two half-cells connected by salt bridge.

• Galvanic cells are spontaneous.

• The salt bridge maintains electroneutrality throughout the cell.

• Electrons move toward more negative electrical potential.

• Oxidation occurs at the anode and reduction occurs at the cathode.

For a three-electrode cell the working electrode is the electrode at which the reaction of interest occurs. The ____ is used to measure the potential of the working electrode and the ___ is the current-supporting partner of the working electrode.

• auxiliary electrode; reference electrode

• reference electrode; polarizable electrode

• cathode; anode

• reference electrode; auxiliary electrode

• potential electrode; reference electrode

For the silver half-reaction, Ag+ + 1 e- → Ag (s), when the concentration of silver cation is increased, the reduction potential:

• remains constant.

• increases or decreases depending on the voltage of the other half-reaction.

• increases or decreases depending on the temperature.

• becomes more positive.

• becomes more negative.

During electrolysis, electrons flow from the ___ terminal of ___ the power supply into the ___ of the electrolysis cell. Electrons flow from the ___ into the terminal of the ___ power supply to complete the circuit

• positive; anode; cathode; negative

• negative; anode; ground; positive

• positive; cathode; anode; negative

• negative; ground; cathode; positive

• negative; cathode; anode; positive

Which is NOT correct for a galvanic cell when the silver and vanadium half-cells are connected via a salt bridge and a potentiometer?

Ag+ + 1 e- → Ag (s) E° = 0.7993 V

V 2+ + 2 e- → V (s) E° = −1.125 V

• I Ag is reduced.

• II V is oxidized.

• III E = 1.924 V

• IV V is reduced.

• V Ag is oxidized.

For indicator electrodes, which statements are true?

• I Indicator electrodes are made from relatively inert metals.

• II Indicator electrodes work best when the electrode surface is large and clean.

• III Platinum is a common indicator electrode.

• IV Platinum electrodes are more inert than gold electrodes.

Starch is an indicator for iodine. For iodimetry, starch solution is added:

• after the equivalence point of the titration has been reached.

• to the titrant before starting the titration.

• right before the equivalence point of the titration

• at the half-way point of the titration

• at the beginning of the titration.