1. Which of the following factors affect the corrosion rate of metal? a) Relative surface area of an anode and cathode b) Nature of the oxide layer c) Purity of metal d) Relative surface area of an anode and cathode, nature of oxide layer and purity of metal 2. The cathodic reaction that occurs during corrosion in oxygenated acidic solution ... Read more

* What is Corrosion? a) Destruction or deterioration of a material b) Conversion of metal atoms to metallic ions c) Conversion of metal ions to metal atoms d) Destruction of materials involving in the conversion of metal atoms into metal ions * The chemical formula of rust is ______ a) Fe1O b) Fe2O3 c) Fe3O4 d) Fe(OH)2 * . Which ... Read more

1. A sheet of carbon steel ONE meter wide by THREE meter long has lost 40 g with a current density of 1.69 X 10-41.69 X 10-4A/cm2 over the past SIX MONTHS. Suppose that only one face of the metal is exposed to corrosive media. Determine the corrosion rate in: (a) mmpy (Millimeter per year) (b) mdd (milligrams per decimeter2 ... Read more

Iron sample (At.wt=56g) with dimensions (10mm x 20mm x 2mm) and density =7.87g/cm3, is exposed to a corrosive environment (neglect thickness for surface area). Just one sides of the sample are exposed to corrosive environment with corrosion current about(icorr) 1.12×10-3 A/cm2). Calculate corrosion rate in mm/y Read more

1. Iron sample (At.wt=56g) with dimensions (10mm x 20mm x 2mm) and density =7.87g/cm3, is exposed to a corrosive environment (neglect thickness for surface area). Just one sides of the sample are exposed to corrosive environment with corrosion current about(icorr) 1.12×10-3 A/cm2). Calculate corrosion rate in mm/y. Read more

* Which of the following products are obtained when a zinc metal is dipped in dilute HCl solution? a) H2, ZnCl2 b) Cl2, ZnH2 c) H2, Cl2 and ZnH2 d) Zn, H2 and Cl2 * 2. Which of the following reactions occurs when iron is immersed in (oxygenated) sea water? a) Fe==>Fe+2+2e, 2H++2e==>H2 b) Fe==>Fe+2+2e, O2+2H2O+4e==>4OH– c) Fe+2+2e==>Fe+2, 4H++O2+4e==>2H2O d) ... Read more

A solution is made up to contain 0.01 M NaOH. What is the theoretical tendency of PB+2PB+2(-0.126V) to corrode in this pH? Read more

1- The emf a cell made of ZINC(-0.76V) (anode) and hydrogen electrode (cathode) immersed in 0.3 M ZnCl2 is +0.590V. What is the pH of the solution? Read more

What is effect of temperature on Zinc corrosion in fresh water? Read more

a) In cathodic protection, corrosion of a metal is minimised by forming a contact to another metal with a higher reduction potential. b) In anodic inhibition, corrosion of a metal is minimised by forming a porous barrier at its surface. c) Iron corrodes more rapidly in salty water because the electrochemical potential is higher. d) Iron corrodes in oxygen-free water. ... Read more