Multiple Choice Questions on Electrochemistry:

1. Which of the following is not a redox reaction?
a) 2Na + Cl2 → 2NaCl
b) Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
c) 2H2 + O2 → 2H2O
d) Zn + CuSO4 → ZnSO4 + Cu

Answer:
- The correct answer is option c) 2H2 + O2 → 2H2O
- This is a synthesis reaction where two hydrogen molecules combine with one oxygen molecule to form two water molecules. There is no change in oxidation states, indicating that it is not a redox reaction.

2. Which of the following is the strongest reducing agent?
a) Na
b) Mg
c) Al
d) Zn

Answer:
- The correct answer is option a) Na
- The reducing power of an element is determined by its ability to lose electrons. Sodium (Na) has a lower ionization energy and readily loses electrons, making it a strong reducing agent compared to the other elements listed.

3. In which of the following half-reactions is reduction taking place?
a) Fe2+ → Fe3+ + e-
b) MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
c) Cl2 + 2e- → 2Cl-
d) 2H2O → O2 + 4H+ + 4e-

Answer:
- The correct answer is option b) MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
- Reduction involves gaining electrons. In the given half-reaction, MnO4- gains 5 electrons to form Mn2+, indicating a reduction process.

4. Which of the following is a non-spontaneous redox reaction?
a) Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
b) Zn + 2HCl → ZnCl2 + H2
c) 2Na + Cl2 → 2NaCl
d) 2Al + 3Pb(NO3)2 → 2Al(NO3)3 + 3Pb

Answer:
- The correct answer is option a) Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
- A non-spontaneous redox reaction is one that does not occur naturally without an external energy source. In this reaction, copper (Cu) displaces silver (Ag) from silver nitrate (AgNO3), which is not spontaneous.

5. Which of the following is an example of a redox reaction used in corrosion protection?
a) Electroplating of silver
b) Galvanization of iron
c) Electrolysis of water
d) Rusting of iron

Answer:
- The correct answer is option b) Galvanization of iron
- Galvanization is the process of coating iron or steel with a layer of zinc to protect it from corrosion. It is a redox