Chemistry MCQ with Answer and Explanation : Oxidation and Reduction.

---

Question 131:

What is the oxidation state of oxygen in H2O2H2​O2​?
A) -1
B) 0
C) -2
D) +2

Answer: A) -1

Explanation: In hydrogen peroxide, oxygen has an oxidation state of -1.

---

Question 132:

In which of the following pairs does one species undergo oxidation while the other undergoes reduction?
A) Fe+Ag+→Fe2++AgFe+Ag+→Fe2++Ag
B) Na+Cl2→NaClNa+Cl2​→NaCl
C) Cu2++Zn→Cu+Zn2+Cu2++Zn→Cu+Zn2+
D) All of the above

Answer: D) All of the above

Explanation: Each reaction involves one species being oxidized and another being reduced.

---

Question 133:

Which of the following compounds is a strong oxidizing agent?
A) Fe3+Fe3+
B) I−I−
C) AgAg
D) KMnO4KMnO4​

Answer: D) KMnO4KMnO4​

Explanation: Potassium permanganate is commonly used as a strong oxidizing agent in redox reactions.

---

Question 134:

What is the oxidation state of zinc in ZnCl2ZnCl2​?
A) +1
B) +2
C) 0
D) -1

Answer: B) +2

Explanation: In zinc chloride, zinc has an oxidation state of +2.

---

Question 135:

In the reaction 2Ag++Zn→2Ag+Zn2+2Ag++Zn→2Ag+Zn2+, which species is oxidized?
A) Ag+Ag+
B) ZnZn
C) Zn2+Zn2+
D) None of the above

Answer: B) ZnZn

Explanation: Zinc loses electrons and is oxidized to Zn2+Zn2+.

---

Question 136:

What is the oxidation state of nitrogen in N2H4N2​H4​?
A) -2
B) 0
C) +1
D) +2

Answer: C) +1

Explanation: In hydrazine (N2H4N2​H4​), the oxidation state of nitrogen is +1.

---

Question 137:

Which of the following statements is true for the reaction 2Ag+Cu2+→2Ag++Cu2Ag+Cu2+→2Ag++Cu?
A) Silver is oxidized and copper is reduced.
B) Copper is oxidized and silver is reduced.
C) Both silver and copper are oxidized.
D) Both silver and copper are reduced.

Answer: A) Silver is oxidized and copper is reduced.

Explanation: Silver loses electrons, while copper gains electrons.

---

Question 138:

What is the oxidation state of the central atom in CrCl3CrCl3​?
A) +3
B) +5
C) +6
D) 0

Answer: A) +3

Explanation: In chromium(III) chloride, chromium has an oxidation state of +3.

---

Question 139:

Which of the following is a product of the reduction of Fe3+Fe3+?
A) FeFe
B) Fe2+Fe2+
C) Fe2O3Fe2​O3​
D) FeOFeO

Answer: B) Fe2+Fe2+

Explanation: The reduction of Fe3+Fe3+ results in Fe2+Fe2+.

---

Question 140:

What is the oxidation state of aluminum in Al2O3Al2​O3​?
A) +1
B) +2
C) +3
D) 0

Answer: C) +3

Explanation: In aluminum oxide, aluminum has an oxidation state of +3.