11. A metal is electrochemically polarised to a potential which is higher than the standard reduction potential of the metal. The overvoltage will be
12. The difference in potential between two standard half cells is ΔE°. If the half cell are galvanically coupled, the value of ΔE°, with changes in concentration of ions in the solution, is such that
13. In electrolytic refining of nickel (Ni), the anode is Cu-10 atom% Ni and the cathode is pure Ni. Assuming the Cu-Ni solution to be ideal, the absolute value of the minimum voltage (in mv) required for refining is.
Given, Faraday's constant = 96490 C mole-1, Temperature = 300 K, R = 8.314 J. mol-1. K-1
Given, Faraday's constant = 96490 C mole-1, Temperature = 300 K, R = 8.314 J. mol-1. K-1
14. Which of the following metals is lowest active in the electrochemical series?
15. Which of the following metals is lowest noble in the Galvanic series?
16. Match the following:
P. Dezincification
1. Reactivation
Q. Flade potential
2. Stainless steel
R. Intergranular corrosion
3. Polarisation
S. Tafel relationship
4. Brasses
| P. Dezincification | 1. Reactivation |
| Q. Flade potential | 2. Stainless steel |
| R. Intergranular corrosion | 3. Polarisation |
| S. Tafel relationship | 4. Brasses |
17. When P-B ratio is less than 1
18. Identify the correct combination of the following statements.
P. Hydrogen electrode is a standard used to measure redox potentials.
Q. Activation polarization refers to electrochemical process controlled by reaction sequence at metal-solution interface.
R. Potential-pH diagrams can be used to predict corrosion rates of metals.
S. Cathodic protection can use sacrificial anodes such as magnesium.
P. Hydrogen electrode is a standard used to measure redox potentials.
Q. Activation polarization refers to electrochemical process controlled by reaction sequence at metal-solution interface.
R. Potential-pH diagrams can be used to predict corrosion rates of metals.
S. Cathodic protection can use sacrificial anodes such as magnesium.