WorksheetsCorrosion & its Control
Total questions: 25
Worksheet time: 17mins
Rusting is a ------- process.
mechanical
physical
chemical
thermal
Chemical formula of rust is
FeSO4
FeS
FeCl2
Fe2O3.xH2O
During rusting of iron, reaction occurring at cathode is
2 Fe (s)→2 Fe2+ + 4 e
O2(g) + 4 H+(aq) + 4 e ⎯→ 2 H2O (l )
2 Zn (s)→2 Zn2+ + 4 e
2 Cu (s)→2 Cu2+ + 4 e
Corrosion can be prevented by
Alloying with other elements
Dehumidification of environment
Cathodic protection
All of the above
Select the WRONG statement
Dry corrosion occurs rarely
Wet corrosion is called immersed corrosion
Wet corrosion takes place by adsorption mechanism
Dry corrosion occurs in the absence of moisture
Metal used to protect iron by cathodic protection
Ag
Cu
Sn
Zn
Agents responsible for rusting of iron
water
oxygen
water & oxygen
oil
Ratio of metal oxide formed to metal consumed is called standard volume ratio.
true
false
Higher the position of the metal in the galvanic series---------- is the corrosion
greater
lesser
not affected
Zinc & magnesium function as------ w.r.t. protection of iron
cathode
anode
alloying metals
sacrificial anodes
Wire mesh at the joints is subjected to ---------corrosion.
galvanic
pitting
differential aeration
differential metal
Sacrificial protection is used for
iron objects
iron railings
underground iron pipes
bridges
Wet corrosion occurs due to
chemical reaction
electrochemical corrosion
Both
When two different metals come in contact with each other in a corrosive environment, what happens?
differential aeration corrosion
galvanic corrosion
both
pitting corrosion
Rate of corrosion of iron in the presence of salt?
no effect
speeds up
slows down
Alkali & alkaline earth metals with oxygen under dry conditions form
stable oxide film
volatile oxide film
unstable oxide film
porous oxide film
In differential aeration corrosion, poorly oxygenated areas behave as
anodic
cathodic
inert
corroded
Forcing a metal to behave as cathode to avoid or prevent from undergoing corrosion is
cathodic protection
pitting
passivity
alloying
Pitting corrosion is a --------- accelerated attack.
non localized
localized
national
Bolts & nuts made of same metal are preferred to avoid-------- corrosion
galvanic
pitting
waterline
surface
Aluminium is resistant to corrosion due to
passivity
non reactive
highly reactive
Smaller the anodic area & larger the cathodic area, then rate of corrosion
increases
decreases
remains same
With increase in temperature the rate of corrosion
increases due to increase in conductivity & diffusion of ions or gases
increases due to decrease in diffusion of ions or gases
decreases due to increase in conductivity
decreases due to increase in diffusion of ions
When iron & zinc come in contact with each other in a corrosive environment, which metal will be prone to corrosion
iron being anode undergoes corrosion
zinc being anode gets prevented from corrosion
iron being cathode gets prevented from corrosion
zinc being cathode gets prevented from corrosion
Liquid metal corrosion is commonly observed in nuclear reactors.
true
false
