1
Quiz
No. Correct: ____
CP3: Cathodic Protection Technologist
Chapter 1
Passing Score = 70%
(6 out of 8 correct)
Duc Nguyen
Name: _______________________________________________________________________________________
++
1. What would be the potential of pure iron to a standard hydrogen electrode if the Fe activity is 0.1 Moles/liter
0
(assume T-273 K) T-298K
A.
-413 mVSHE
B. -440 mVSHE
C. -467 mVSHE
D. +467 mVSHE
2. The Pourbaix Diagram predicts corrosion by relating the following factors.
A.
Potential across a metal interface and pH
B.
Open circuit potential of the anode compared to the open circuit potential of the cathode
C.
Closed circuit potential of the anode compared to the closed circuit potential of the cathode
D.
The length of time for a known amount of current
3. According to the EMF series, which material(s) could be used as a galvanic anode material for copper?
I.
Magnesium
II.
Zinc
III.
Iron
IV.
Aluminum
A.
I only
B.
I & II only
C.
I, II & III only
D.
I, II, III & IV
NACE International
Use galvanic series
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0
4. If the references used in the following potential measurements are at 25 C, which one(s) are equivalent
to -912 mVCSE?
I.
-596 mVSHE
II.
-862 mVssc(SJ)
III.
+204 mVZre
IV.
-857 mVsce
A.
I only
B.
I & III only
C.
II & IV only
D.
I, II & IV only
-912
-912 + 60 = -852
-912 + 72 = -840
-912 + 316 = -596
-912 + 1116 = + 204
Metal here
5. Which one of the following would result in the largest corrosion rate according to Faraday's Law?
1 ft = 30.48cm, 1ft2 = 929.0304 cm2
A.
A discharge current density of 10mA/ft2 from a steel plate 0.0107mA/cm2 --> r = 55.85/(2*96500) * (0.0107/1000)/7,87
B.
A discharge current density of 6µA/cm2 from a lead plate r = 207.19/(2*96500) * (6/10^6)/11.3 = 5.7 x 10^-10
C.
A discharge current density of 100 mA/m2 from a zinc anode r = 65.37*(2*96500)*(100/1000/10^4)/7.14 = 4.74 x 10^-10
D.
A discharge current density of 10µA/cm2 from an aluminum anode r = 26.98*(3*96500)*(10/10^6)/2.70 = 3.45 x 10^-10
= 3.93 x 10^-10
6. An increase in corrosion rate in a corrosion cell could be caused by which of the following?
I.
increase in metal ion concentration at the anode
II.
decrease in ion concentration in the electrolyte
III.
increase in cathode polarization
IV.
increase in AC current density
more positive, less drive voltage
higher resistor
lower driven voltage, less corrosion rate
depolarizer
A.
IV only
B.
I & III only
C.
II & IV only
D.
I, III & IV only
NACE International
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7. Which of the following satisfies the -850mVcse criterion @ at 250C?
I.
0
A potential of -864 mV with respect to a copper sulfate reference electrode @ 40 C. -864mV + 0.9 * 15 = -850.5
II.
0
A potential of -823 mV with respect to a copper sulfate reference electrode @ -5 C. -823 +0.9 *(-30) = 850 mV
mV CSE
CSE
III.
0
A potential of -746 mV with respect to a saturated silver chloride reference electrode @ 15 C.
IV.
0
A potential of -785 mV with respect to a saturated calomel reference electrode @ 40 C.
-746 + (-0.7) * (-10) = -739mV SSC = (-739 - 94) = -833 mV CSE
-785 + (-0.7) * 15 = -795.5mV SCE = -795.5 - 72 = -867.5mV CSE
A.
II only
B. I & II only
C. I, III & IV only
D. I, II, & IV
8. Convert -880 mV/SCE to the equivalent mV/CSE?
-880mV - 72mV = -952mV
A.
-952mV/CSE
B. -805mV/CSE
C. +995mV/CSE
D. +805mV/CSE
NACE International
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