Electrochemical Series and Its Applications - UNSOLVED PRACTICE SET

Q7. Write the electrochemical series for the following metals (in order of increasing reduction potential): K, Na, Ca, Mg, Al, Zn, Fe, Ni, Sn, Pb, H, Cu, Ag, Au.

Q8. Based on the electrochemical series, predict whether the following reactions will occur:

(a) Cu + 2Ag⁺ → Cu²⁺ + 2Ag

(b) Fe + Zn²⁺ → Fe²⁺ + Zn

Give reasons for your predictions.

Q9. Why can aluminium displace iron from Fe₂O₃ in the thermite reaction, even though aluminium has a protective oxide layer?

Q10. What is the difference between the activity series and the electrochemical series?

Q11. Your school has iron railings that are rusting, while the copper dome on the building remains shiny. Explain this observation using the electrochemical series.

Q12. Why is sodium extracted by electrolysis of molten NaCl, while iron is extracted by reduction with carbon? Use the electrochemical series to explain.

Q13. Discuss the electrochemical series and its applications:

(a) Construction of the electrochemical series based on standard reduction potentials

(b) Comparison of reactivity of metals — reducing power decreases down the series

(c) Comparison of reactivity of non-metals — oxidising power increases down the series

(d) Predicting the feasibility of displacement reactions

(e) Predicting whether a metal will react with dilute acids to liberate hydrogen

(f) Predicting the products of electrolysis

Q14. Explain the applications of the electrochemical series in detail:

(a) Predicting displacement reactions — with examples (Zn displacing Cu, Cu displacing Ag)

(b) Predicting corrosion tendency — metals with more negative E° corrode more easily

(c) Predicting feasibility of extraction — why reactive metals need electrolysis while less reactive ones can be reduced by carbon or CO

(d) Construction of galvanic cells — selecting appropriate electrode pairs

(e) Predicting reducing and oxidising strengths of elements

Q15. The electrochemical series guides India's metallurgical and industrial sectors. Discuss:

(a) Why aluminium production in India (Hindalco, NALCO) uses the Hall-Heroult electrolytic process

(b) Why iron and steel production uses blast furnace reduction rather than electrolysis

(c) How the electrochemical series explains why zinc galvanisation protects India's railway infrastructure

(d) The challenge of extracting rare earth elements in India and how E° values guide process selection

Q16. Given the following standard reduction potentials:

E°(Mg²⁺/Mg) = -2.37 V

E°(Al³⁺/Al) = -1.66 V

E°(Zn²⁺/Zn) = -0.76 V

E°(Fe²⁺/Fe) = -0.44 V

E°(Ni²⁺/Ni) = -0.25 V

E°(Cu²⁺/Cu) = +0.34 V

E°(Ag⁺/Ag) = +0.80 V

(a) Arrange these metals in order of increasing tendency to lose electrons.

(b) Identify which metals can displace hydrogen from dilute HCl and write one representative reaction.

(c) Calculate the standard EMF of the cell with the highest possible voltage using these half-cells.

Q17. A piece of iron and a piece of copper are connected and immersed in seawater (electrolyte).

(a) Using the electrochemical series, identify which metal will corrode and which will be protected.

(b) Write the anode and cathode reactions.

(c) If the corrosion current is 0.1 A, calculate the mass of iron corroded in 1 year.

[Given: Atomic mass of Fe = 56 g/mol, F = 96500 C/mol]

Q18. India's annual steel production is approximately 120 million tonnes, mostly from iron ore (Fe₂O₃) reduction.

(a) Using the electrochemical series, explain why carbon (coke) can reduce Fe₂O₃ but not Al₂O₃.

(b) Calculate the theoretical mass of carbon required to produce 120 million tonnes of iron from Fe₂O₃.

(c) If the actual carbon consumption is 1.5 times the theoretical amount due to process inefficiencies, calculate the total CO₂ emissions from this steel production.

[Given: Atomic masses: Fe = 56, C = 12, O = 16]