Q1. Which of the following reactions is a reduction? (2020)
Solution:
In the reaction Fe2O3 + 3CO → 2Fe + 3CO2, iron (Fe) is reduced as it gains electrons from carbon monoxide (CO).
⏱ Time: 0s
Q2. In the reaction 4Fe + 3O2 → 2Fe2O3, which element is oxidized?
Solution:
Iron (Fe) is oxidized as it loses electrons to form Fe2O3.
⏱ Time: 0s
Q3. In the redox reaction 2Ag+ + Zn → 2Ag + Zn2+, which species is oxidized? (2021)
Solution:
Zn is oxidized to Zn2+ as it loses electrons.
⏱ Time: 0s
Q4. In the reaction Zn + CuSO4 → ZnSO4 + Cu, which species is reduced?
Solution:
Copper (Cu) is reduced as it gains electrons from zinc.
⏱ Time: 0s
Q5. Which of the following species acts as a reducing agent in the reaction 2Fe2O3 + 3C → 4Fe + 3CO? (2022)
Solution:
Carbon (C) acts as a reducing agent as it donates electrons to reduce Fe2O3 to Fe.
⏱ Time: 0s
Q6. In the redox reaction 2MnO4- + 5C2O4^2- + 16H+ → 2Mn^2+ + 10CO2 + 8H2O, what is the oxidation state of carbon in C2O4^2-?
Solution:
In C2O4^2-, the oxidation state of carbon is +3.
⏱ Time: 0s
Q7. In the reaction 3H2 + N2 → 2NH3, which element is reduced? (2022)
Solution:
N2 is reduced to NH3 as it gains electrons.
⏱ Time: 0s
Q8. In the redox reaction 2Ag+ + Cu → 2Ag + Cu2+, which species is oxidized? (2022) 2022
Solution:
Cu is oxidized to Cu2+ as it loses electrons in the reaction.
⏱ Time: 0s
Q9. What is the oxidation state of sulfur in H2SO4? (2021) 2021
Solution:
In H2SO4, the oxidation state of sulfur is +6. Each hydrogen is +1 and each oxygen is -2, leading to the equation: 2(+1) + x + 4(-2) = 0, solving gives x = +6.
⏱ Time: 0s
Q10. Which of the following reactions involves a redox process? (2019)
Solution:
H2O → H2 + O2 involves the oxidation of water to hydrogen and oxygen, making it a redox reaction.
