Lesson 3: Electrochemistry And Corrosion Flashcards
1
Q
- In a bimetallic couple, the less noble material becomes the ______ and tends to corrode at an accelerated
rate, compared with the uncoupled condition and the more noble material will act as the _______ in the
corrosion cell.
a. Cathode, anode
b. Anode, cathode
c. Anion, cation
d. Cation, anion
A
B. Anode, cathode
2
Q
- A conductive solution, like saltwater or even tap water, that allows the flow of ions between the anode and
cathode.
a. Solvent
b. Electrons
c. Reagents
d. Electrolyte
A
D. Electrolyte
3
Q
- It refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte.
a. Electromagnetic corrosion
b. thermal corrosion
c. Galvanic corrosion
d. Galvanic corrodent
A
c. Galvanic corrosion
4
Q
Using the galvanic series table of some commercial metals and alloys in seawater, which among the following is properly arranged in a descending order based on their nobility?
a. Zinc, cadmium, platinum
b. Lead, tin, copper
c. Graphite, monel, lead
d. Gold, copper, platinum
A
c. Graphite, monel, lead
5
Q
- The metal that is protected from corrosion. It receives electrons and undergoes reduction. MORE NOBLE
a. Cathode
b. Cation
c. Anode
d. Anion
A
A. Cathode
6
Q
- Choose which statement is true
a. The higher the electrode potential, the higher the tendency to gain electrons.
b. The higher the electrode potential, the higher the tendency to lose electrons.
c. The higher the electrode potential, the lower the tendency to lose electrons.
d. The higher the electrode potential, the lower the tendency to gain electrons.
A
B. The higher the electrode potential, the higher the tendency to lose electrons.
7
Q
- The standard electrode potential is measured at
a. 1000 bar
b. 760 mmHg
c. 8000 Pa
d. 3 atm
A
b. 760 mmHg
8
Q
- Do electrons always flow from cathode to anode?
a. Yes
b. No
A
B. No
9
Q
- The reduction potential value is positive when ___
a. It is less electropositive than hydrogen
b. It is more electropositive than hydrogen
c. It is equal to the standard hydrogen electrode potential
d. None of the above
A
a. It is less electropositive than hydrogen
10
Q
- Which of the following describes the relationship between the zinc half cell and the copper half
cell in an electrochemical cell?
a. Zinc half cell gains electrons from the copper half cell, making zinc the cathode.
b. Zinc half cell loses electrons to the copper half cell, making zinc the anode.
c. Copper half cell gains electrons from the zinc half cell, making copper the anode.
d. Copper half cell loses electrons to the zinc half cell, making copper the cathode
A
b. Zinc half cell loses electrons to the copper half cell, making zinc the anode.
11
Q
- What is produced in an electrochemical cell while corrosion is occurring?
a. Corrosion current
b. Corrosion charge
c. Corrosion rate
d. None of the above
A
A. Corrosion current
12
Q
- ____________ involves the transfer of electrons from the anode to the cathode.
a. Chemical corrosion
b. Electrochemical corrosion
c. Electrochemistry
d. None of the above
A
C. Electrochemistry
13
Q
- 1 Faraday = _______________
a. 1 coulomb
b. 1000 coulomb
c. 5000 coulomb
d. 96500 coulomb
A
d. 96500 coulomb
14
Q
- Electrochemical equivalent may be defined as the ____________ of the substance deposited by
the passage of 1 coulomb of electricity.
a. Volume
b. Weight
c. Density
d. None of the above
A
B. Weight
15
Q
- According to Faraday’s first law of electrolysis, the amount of any substance deposited at the
electrode is directly proportional to the quantity of _______________
a. Voltage drop
b. Resistance
c. Electricity passed
d. Tolerance
A
c. Electricity passed
16
Q
- Which kind of reaction occurs at anode?
a. Oxidation
b. Displacement
c. Reduction
d. Decomposition
A
A. Oxidation
17
Q
- What is the name of the devices that are capable of converting chemical energy into electrical
energy, or vice versa.
a. Photochemical Cell
b. Electric Cell
c. Photoelectric Cell
d. Electrochemical Cell
A
d. Electrochemical Cell
18
Q
- Which electrode is denoted by a negative sign?
a. Cathode
b. Anode
c. Diode
d. None of these
A
B. Anode
19
Q
- Corrosion can be prevented by?
a. Tinning
b. Alloying
c. Galvanizing
d. All of the Above
A
d. All of the Above
20
Q
- The ions in a solution which conduct electricity are known as?
a. Electrolytes
b. Colloids
c. Electrions
d. Electrons
A
a. Electrolytes
21
Q
These devices are capable of converting chemical energy into
electrical energy, or vice versa.
A
Electrochemical Cell
22
Q
Classification of Electrochemical Cell
A
Galvanic cell
Electrolytic cell
23
Q
Converts chem energy to electrical energy
A
Galvanic cell
24
Q
Redox reax is spontaneous and responsible for the production of electrical energy
A
Galvanic cell
25
In galvanic cell, anode is ___ and cathode is ___
Negative
Positive
26
Move from anode to cathode
Galvanic cell
27
Oxidation: ___ of electrons
Reduction: ___ of electrons
Loss
Gain
28
Converts electrical energy to chem energy
Electrolytic cell
29
Redox reax is __ in Electrolytic cell and EE has to be ___ to initiate the reax
Not spontaneous
Supplied
30
Enter through the cathode and come through the anode
Electrolytic cell
31
____ also called “___" or wrongly
“electrolysis”) refers to corrosion damage induced when
two dissimilar materials are coupled in a corrosive
electrolyte.
Galvanic corrosion
dissimilar metal corrosion
32
In a bimetallic couple, the *less noble* material becomes the __ and tends to corrode at an accelerated rate
anode
33
*more noble* material will act as the __ in the corrosion cel
cathode
34
The metal that corrodes preferentially. It loses electrons and experiences oxidation. LESS NOBLE
Anode
35
The metal that is protected from corrosion. It receives electrons and undergoes reduction. MORE NOBLE
Cathode
36
___: A conductive solution, like saltwater or even tap
water, that allows the flow of ions between the anode and
cathode.
Electrolyte
37
Factors influencing galvanic corrosion
-The relative nobility of the metals
-Surface area ratio
-Electrolyte conductivity
38
A __ difference in nobility leads to a
faster corrosion rate for the anode.
larger
39
A *larger anode area* compared to the cathode area experiences a __ corrosion rate, and vice versa
slower
40
___ conductivity allows for a greater flow of ions, accelerating the corrosion process.
Higher
41
Preventing galvanic corrosion
Material selection
Electrical isolation
Coating
Sacrificial anodes
42
It is the tendency for an electrode to lose or gain electrons when dipped
in the solution of its ions
Electrode potential
43
Standard Electrode Potential is measured at
1 atm
298K
1M
44
Electrode Potential Values
Positive
Negative
45
__ is produced in an electrochemical cell while **corrosion is occurring**
Current
46
__ involves the transfer of electrons from the **anode to the cathode**.
Electrochemical corrosion
47
**Speed** at which any given **metal deteriorates** in a
specific environment.
Corrosion rate
48
Corrosion rate is dependent on
Environmental Conditions
Type & Condition of Metal
49
Electrochemical corrosion rate is “___”
instantaneous
50
Discovered by Michael Faraday in the 19th Century
Faraday’s First Law of Electrolysis
51
Faraday developed the __ known as
"FARADAY"
number of coulombs
52
Charge of one mol of electron (6.022x10^23 electrons) will then be __
96,485 C.
53
Charge on the electron is __ (Coulomb).
1.6x10^-19 C
54
One mole of metal contains Avogadro’s number (___ ) of metal atoms.
6.022x10^23
55
Faraday’s First Law of Electrolysis
This law states that:
Amount of substance produced at each electrode is _ to the
charge flowing through the cell.
directly proportional
56
In faraday's first law of electrolysis, z is a constant known as __ and characteristic of the substance deposited.
electro-chemical equivalent
57
aka galvanic cell or voltaic cell
Electrochemical cell
58
Galvanic cell is named after __
Luigi Galvani
59
Components of electrochemical cells
Cathode
Anode
Electrolyres
Salt bridge
60
Device used in Ecell for connecting its oxidation and reduction half cells wherein an *inert electrolyte* is used
Salt bridge
61
Types of electrochemical cells
Dissimilar electrode cell
Concentration cell
Differential temperature cell
62
These cells incolve diff types of metals or metal compositions coming into contact, leading to electron transfer between them
Dissimilar electrode cell
63
2 types of concentration cells
Salt CC
Differential aeration cell
64
Cells with 2 identical electrodes, each in contact with a soln of diff composition
Salt concentration cell
65
Occurs due to differences in potential bet. differently aerated areas
Differential aeration cell
66
Type of cell when 2 identical electrides are immersed in same elctrolytes but the electrodes are immersed into solution of *two different temperatures*
Differential temperature cell
67
A list that describes the arrangement of elements in the order of their increasibf electrode potential values
Electrochemical series
68
Orderly arrangement of the standard potentials for all metals
Emf series
69
In emf series, the more __ the values, the more reactive the metals
Negative
70
Galvanic cell is where ___ reaction occurs while electrolytic cell ____ reaction occurs
Spontaneous
Non spontaneous
71
Determines the electrochemixal potential and nobility of metals (and metal alloys)
Galvanic series
72
Ranking of metals and alloys according to their free corrosion potential in a given electrolyte
Galvanic series
73
Galvanic corrosion or
Bimetallic corrosion
74
The ___ a metal or an alloy is in the galvanic series, the less are the effects of galvanic corrosion compared to those metals ___.
Closer
Far apart
75
Electrode potential is only negative. T or F.
F. Can either be + or -
76
___ can be used to measure potential differences
Voltmeter
77
Produced when electrons flow through anode to cathode
Current
78
Half reaction of standard hydrogen electrode or SHE
2H+ (aq) + 2e- <----> H2 (g)
79
In SHE, why platinum is used
1. Relatively inert, does not corrode easily
2. Has catalytic qualities, promote proton reduction reaction
3. Improve reaction kinetics
80
Pure mercury is placed at the bottom of the tube, which is covered with a paste of mercury-mercurous cl (hg+hg2cl2)
Calomel reference electrode
81
Pure Hg covers a Pt wire sealed thru the bottom of a glass tube
Calomel reference electrode
82
Composed of a silver wire, sometimes coated witj a layer of solid silver chloride, immersed in a soln that is saturated with KCl and AgCl
Silver-silver chloride reference electrode
83
Like the calomel electrode, the potential is more active the higher the KCl concentration
Silver-silver chloride reference electrode
84
Consists of metallic copper immersed in saturated cu sulfate
Saturated cu-cu sulfate reference electrode
85
Precision is slightly lower than calomel and AgCl electrodes but still sufficient for most corrosion studies
Saturated cu-cu sulfate reference electrode
86
Speed at which any metal deteriorates
Corrosion rate
87
A reduction current that occurs when electrons flow from electrode surface to a species in a soln
Cathodic current
88
A oxidation current that occurs when electrons flow from electrode surface to a species in a soln
Anodic current
89
Occurs when the electrolyte resistance is so high that the resultant current is not sufficient to appreciably polarize anodes and cathodes
Resistance control
90
Can be calculated if the *anode-cathode area ratio* can be estimated
Corrosion current
