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Quiz
1.
The elements of a corrosion cell include which of the following?
. !node . "athode . #lectrol$te %. #lectronic &ath onl$ , & ll onl$ , ll % onl$ , , 1,11 & % .
!. (. ". D. ).
*arada$'s +aw calculates the &otential of a metal in seawater. &otential of a metal in the metal ion solution. metal lo lost st ased on the resistance . metal lost due to current oer time.
!. (. ". .
..
/.
the e following? 0eference electrodes include which of th . "o&&er -co&&er -co&&er sulfate . $drogen . "alomel %. 2iler-siler chloride
A.
onl$ & onl$ , ,, ll & % , %
(. ". .
onl$ 3.
efe rence ce electrode does not ar$ with The stailit$ of a co&&er-co&&er sulfate r eferen !. !. (. ". D.
tem&erature. e4&osure to sunlight. an unsaturated solution of co&&er ions. a saturated solution of the co&&er ions.
ernational 2005 567 NACE I nt ernationa , ,
120/05 06 12
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8. f a &otentia l of -393 m% is measured with res&ect to a h$drogen electrode, what is the &otential to co&&er-co&&er sulfate? !.
".
-1:9 %"2# (. -/1: m%"2# -9;; m%cs# ·
D.
-111: m%cs# :.
f a &otentialof -<;; m% is measured with res&ect to a co&&er-co&&er sulfate reference, what is the &otentia l to a zinc electrode? !. B.
C. D.
=)1: m%z> · =111: m%z> -)1: m%z> -);1: m%z>
7. f a digital meter dis&la$s a negatie aluewhile measuring a oltage across a resistor, it indicates that the · · !. current is from· the &ositie to th.e negatie meter connection, B. current is from the negatie to the &ositie meter connectto n C. meter is reading incorrectl$. · D. meter scale should e changed. 8.
?olarization occurs A. B.
". D.
at the anode surface onl$. at the cathode surface onl$. at the anode and cathode surfaces. , in the metallic &ath.
<. @hich of the following are de&olarizers? . issoled o4$gen . ncreased electrol$te elocit$
(acteria action % . "urrent &icAu& on the metal Ill.
!. B.
onl$ only
J
.
C. .
, ll onl$ · , , ll %
1;. @hich of the following factors affect &olarization? . "urrent . lon concentration ll. !nodeBcathode ratio %. Tem&erature !. (. ". .
onl$ onl$
ll onl$ , , ll %
11. @hich of the following are t$&es of &olarization?
. "oncentration . !ctiation ll. Tem&erature % . %elocit$ !. (. ". .
onl$ & onl$ & ll onl$ , ,. ll . %
12. The measure of the electrochemical difference etween two ·metals n an electrol$te is which of the following? !. (.
!m&eres . %olts Chms C. . 2iemans
13. The relationshi& etween current and &olarization is descried by which of the following? . "urrent decreases with increased &olarization . olarization increases with increased current. ll. "urrent increases with increased &oDarization % . olarization decreases with increased curren !. (. ". .
onl$ onl$ onl$ ll % onl$
13. ! &assiating mater ial will e4hiit which of the following &r o&erties?
. oes· not corrode at all. &. "orrosion increases as. current increases initiall$. ll. "orrosion curr ent decreases after a certain &oint. %. "orr osion cur r ent increases e$ond the &assie r egion. !. (. ". .
onl$ onl$ , ll % onl$ ll % onl$ 1
18. Eien #1 ·F ); %, 01 F1; ;, 0) = /; the current in 01? Gshow worAH
n, 0/ = /; ;, and 03- /; ;
what is
. ;.)< !. ;,:7 ! (. ! C. 1.; ! · . ).;!
1:. Eien #1 :; %, 01'F1' ; ;, 0) F /; the cur rent in 06c? Gshow worAI =
!, (. ". .
n, 0/ = /; ;, and 03 - /; n what is
;.9: ! 1.;! ).;! /.;!
17. n a standar d emf series of metals, which of thfollowing is r e&resent ed? !. (. ".
.
The &otential oi a met al is measured in a satur ated solution of co&&er -sulfate. "urrent is measured etween the most nole and most actie me tals. The &otenttal is measur ed with res&ect to a standar d h$drogen electr GHde. The total numer of electr ons is determined.
19. f two diff er ent metals are connected together ih ail electrol$te, the metal w ith the
A. (.
C. .
most negatie &otential is the cathode. most &ositie &otential is the cathode. &ositie. &otential will corrode. highest alence is the anode.
19. n a &ractica l galanic series of metals,which of the following is re&resented? -
!.
The &otential etween two different metals in the series is measured.. (. The current is measured etween two of the metals in the serie'JH·. ". The electrol$te contains metal ions of that The &otential of metals in a common metal. . electrol$te.
);. The >e?st eK uation !. (. ". ;.
calculates the change in resistance of the el ctrol$te due to . tem&erature. calculates the &otential of a metal in solutions of different metal ion concentrations. shows the &otential .is &ro&ortional to *arada$'s "onstant. shows the &otenti'al is inersel$ &ro&ortional to the uniersal gas constant
)1. ! corrosion cell can fotm under which of the following conditions? !. (. ". .
! difference in tem&erature where the higher tem&erature is the cathode. ! diffe ence in o4$gen where the highest concentration of o4$gen is at the anode. ! difference in metals where the anode is at the most nole . metal. · ! difference in salt concentration wher e the anode is at the highest ion concentr ation.
.
.
.
)). @hen are metal &asses under a &aed road s.urtace, !. (. " · .
an o4$gen concentration corrosion cell can deelo& with the metal under the &aement eing the anode.. · an o4$gen concentration cell. can deero& with the ·metal outside the &aement eing the anode. a tem&.erature corrosion.cell can deelo& with the metal outside the &aemenLt eing the anode. ! high salt concentration at the .edge of the &aement with the metal under the &aement eing the anode.
)/. !n un&rotected metal structur e moing through an e.lectrol$te will e4&erience !. ·(. ".
;.
· Dess corrosion eEause it sta$s deah. less corrosion ecause lt hel&s &olarization. more corrosion due to decreased &olarization. more corrosion due to stra$ current.
1.
!n enironment where cathodic &rotection is NOT effectie is A
. B.
C. D. 2.
liKuid.' soil. atmos&her icall$ e4&osed surface6 steel in concrete.
The cath odic &r otection criteria for steel i ncludes which·of the following? ·
. ! &otential of -98; m%cs# or mor e negatie with current a&&lied after 0 dro& is co nsidered. . ! &olarized &otential of -850 m%cs# or'more·negatie. ll. olarization of 100 m% or gr eater %. ! &olar ized &otential of -7<; 111% !g. !g"J or '?re negat,D e. A.
1 onl$
B.
on l$ ll onl$ , , ll %
c. .
/.
@hen cathodic &rotection is a&&lied to a corroding steel sur f aceMit ·shNfts the cor r osion Kell · ·· · · &otential as f ollows6 !.
>o change in &otenti a l
(.
c"JtltKK,rrKr e f'l at $.e
D.
cathode hlore &o si tie· anode more &ositie
c. 3.
,.
:.
"athodic &rotection &olari zes the o&en circuit &otential of the structure anode to the structur e cathode &otential. the o&en circuit &otential of the structur e cathode to the str ucture anode a. & otential. ". the o&en circuit &otential of the str ucture cathode to the " anode &o tential. . the o&en circuit " anode &otential to ltHe structur e cathode &otential. . .
A.
8.
%'%hat i s the curr ent reKuired to &rotect an underground are steel tan that i s /m G<.9 ftH in diam eter and 5 m {16. ftH long in resistiit$ of 10,000 ;-cm assuming .1;.7:Brn !tm will &roide &rotection?
A. B. ". .
371
m! #3 rn! :8: rn! 783 rn !·
2
2 !1 m !ift " ·
:.
The current reKuirement for cathodic &rotect ion of a structure will increase with a A. &. B.
". D.
decrease in
decrease in tem&erature. decrease in o4$gen. decrease in elocit$.
7. f lead, co&&er , steeland aluminum are connected together in water, whi
c. . 9.
+ead · · "o&&er 6 2teel !lumihu.m
n a galanic anode s$stem, the driing oltage is due to the . A.
eiectrol$te itself., 6 ·.·· . · B. anode to structu'recou&le in the connection to the structure. electr'ol$te.· ". anode acAfill. · . <.
·
@hich is NOT a &rimar$ re action at the anode? ! (. ". .
O t+<4iK,at.i?,n C4$gen eolution. "hloride eolution $drogen olution,
· .
..·
:
,·
6
1;. @hich of the f ollowing will. decrease cathodic &rotectlo'ffcmrerit. r eKuireOents? . ·.· . .
!.
(. ". .
ncreased & ncreased o4$gen ncreased tem&erature ncreased agitatl&n
