Redox concepts oxidation numbers and balancing redox reactions - One Line Questions
1.
What is the oxidation number of oxygen in H₂O₂? —
-1
2.
What is the oxidation number of oxygen in O₂F₂? —
+1
3.
What is the oxidation state of oxygen in OF₂? —
+2
4.
What is the oxidation number of chlorine in HClO₄? —
+7
5.
What is the oxidation state of chlorine in NaClO₃? —
+5
6.
Which of the following is the most likely oxidation state of iodine in IF₅? —
+5
7.
What is the oxidation number of sulfur in the sulfate ion (SO₄²⁻)? —
+6
8.
What is the oxidation state of manganese in KMnO₄? —
+7
9.
What is the oxidation state of phosphorus in P₄O₁₀? —
+5
10.
What is the oxidation state of iron in Fe₃O₄? —
+8/3
11.
What is the oxidation state of sulfur in Na₂S₂O₃ (sodium thiosulfate)? —
+2.5
12.
In the reaction 3NO₂ + H₂O → 2HNO₃ + NO, what is the oxidation state of nitrogen in NO? —
+2
13.
What is the oxidation state of nitrogen in NH₃? —
-3
14.
What is the oxidation state of phosphorus in H₃PO₄? —
+5
15.
What is the oxidation number of phosphorus in PCl₃? —
+3
16.
What is the oxidation state of chlorine in ClF₃? —
+3
17.
What is the oxidation state of sulfur in H₂S₂O₇ (oleum)? —
+6
18.
What is the oxidation state of carbon in CH₄? —
-4
19.
What is the oxidation number of chromium in CrO₅? —
+8
20.
What is the oxidation number of nitrogen in N₂O₅? —
+5
21.
In the reaction 2Na + Cl₂ → 2NaCl, what is the oxidation state of sodium in NaCl? —
+1
22.
What is the sum of oxidation numbers of all atoms in K₂Cr₂O₇? —
0
23.
What is the oxidation state of carbon in CO₂? —
+4
24.
What is the oxidation number of sulfur in S₈? —
0
25.
In the Haber process (N₂ + 3H₂ ⇌ 2NH₃), what is the oxidation state of nitrogen in NH₃? —
-3
26.
What is the oxidation number of carbon in C₆H₁₂O₆ (glucose)? —
0
27.
Balance the following redox reaction in acidic medium: Cr₂O₇²⁻ + SO₂ → Cr³⁺ + SO₄²⁻. What is the coefficient of SO₂? —
3
28.
Balance the reaction: MnO₄⁻ + S²⁻ → Mn²⁺ + S (in acidic medium). What is the coefficient of S²⁻? —
1
29.
Balance the following redox reaction in basic medium: ClO⁻ + Cr(OH)₃ → Cl⁻ + CrO₄²⁻. What is the coefficient of Cr(OH)₃? —
2
30.
Balance the reaction: BrO₃⁻ + Br⁻ → Br₂ (in acidic medium). What is the coefficient of BrO₃⁻? —
1
31.
Balance the reaction: C₂O₄²⁻ + MnO₄⁻ → CO₂ + Mn²⁺ (in acidic medium). What is the coefficient of MnO₄⁻? —
1
32.
Balance the following redox reaction in basic medium: Ni(OH)₂ + N₂O₄ → Ni₂O₃ + NO₂⁻ + H₂O. What is the coefficient of N₂O₄? —
2
33.
Balance the reaction: P₄ + OH⁻ → PH₃ + PO₄³⁻ (in basic medium). What is the coefficient of P₄? —
1
34.
Which of the following is not a redox reaction? —
Neutralization of HCl by NaOH
35.
Identify the oxidizing agent in the reaction: 5Fe²⁺ + MnO₄⁻ + 8H⁺ → 5Fe³⁺ + Mn²⁺ + 4H₂O —
MnO₄⁻
36.
Which element is reduced when H₂S reacts with Br₂ to form HBr and S? —
Br
37.
Which species is reduced in the reaction: 5H₂O₂ + 2MnO₄⁻ + 6H⁺ → 5O₂ + 2Mn²⁺ + 8H₂O? —
MnO₄⁻
38.
In the reaction 2H₂S + SO₂ → 3S + 2H₂O, what is oxidized? —
H₂S
39.
Identify the reducing agent in the reaction: I₂ + 2S₂O₃²⁻ → 2I⁻ + S₄O₆²⁻ —
S₂O₃²⁻
40.
Which of the following is a characteristic of a reducing agent? —
It causes oxidation
41.
In the reaction: 2KClO₃ → 2KCl + 3O₂, what is oxidized? —
O
42.
In the reaction 2KMnO₄ + 16HCl → 2KCl + 2MnCl₂ + 5Cl₂ + 8H₂O, what is oxidized? —
Cl (in HCl)
43.
Which species acts as a reducing agent in the reaction: 2KMnO₄ + 10FeSO₄ + 8H₂SO₄ → K₂SO₄ + 2MnSO₄ + 5Fe₂(SO₄)₃ + 8H₂O? —
FeSO₄
44.
In which of the following compounds does manganese exhibit its highest oxidation state? —
KMnO₄
45.
Which element is reduced in the reaction: 2Na + Cl₂ → 2NaCl? —
Cl
46.
The process of gaining electrons is known as: —
Reduction
47.
In a redox reaction, the substance that gains electrons is said to be: —
Reduced
48.
In a redox reaction, the substance that loses electrons is said to be: —
Oxidized
49.
Which of the following is a strong oxidizing agent? —
KMnO₄
50.
Which element is oxidized in the reaction: Zn + CuSO₄ → ZnSO₄ + Cu? —
Zn