Short Response Questions

1) What is oxidation state?

2) What is the oxidation number of Cr in chromic acid (H2CrO4)?

3) Identify reducing agent in the following reaction. CuO + H2 → Cu + H2O

4) Why tin plated steel is used to make food cans?

5) Explain on example from daily life which involves oxidation-reduction.

6: Compare and contrast oxidation and reduction.

7: Define oxidation and reduction in terms of loss or gain of electrons.

8: Explain how food and beverage industries deal with corrosion.

9: State the substances which are oxidized or reduced. Give reason for your answer.

Equations:

  • N2 + 3H2 → NH3
  • CO2 + 2Mg → 2MgO + C
  • Mg + H2O → MgO + H2
  • H2S + Cl2 → 2HCl + S
  • 2NH3 + 3CuO → 3Cu + N2 + H2O

10: a) Define oxidation number or oxidation state.

b) Find the oxidation state of Nitrogen in the following compounds.

  1. NO2
  2. N2O
  3. N2O3
  4. HNO3

11: Find the oxidation state of S in the following compounds.

  1. H2S
  2. H2SO3
  3. Na2S2O3

12: a) Define oxidizing and reducing agents.

b) Identify the oxidizing agents and reducing agents in the following reactions:

EquationOxidizing AgentReducing Agent
H2S + Cl2 → 2HCl + SCl2H2S
2FeCl2 + Cl2 → 2FeCl3Cl2FeCl2
2KI + Cl2 → 2KCl + I2Cl2KI
Mg + 2HCl → MgCl2 + H2HClMg

13: Hydrogen peroxide reacts with silver oxide and lead(II) sulphide according to the following equations. Is hydrogen peroxide an oxidizing or reducing agent in these reactions? Argue.

  1. H2O2 + Ag2O → 2Ag + H2O + O2
  2. 4H2O2 + PbS → PbSO4 + 4H2O

14: Distinguish between a redox reaction and a non-redox reaction based on the involvement of electron transfer and changes in oxidation states.

15: Analyze the following reaction: Zn + 2H+ → Zn2+ + H2. Based on the oxidation numbers, identify the species oxidized and reduced.

16: Given the reaction: I2 + 2NaHCO3 → NaI + NaIO3 + CO2 + H2O, what is the oxidation number of carbon in the bicarbonate ion (HCO3-) and the carbonate ion (CO32-) and CO2?

17: Identify the oxidizing agent and reducing agent in the following reaction: Sn2+ + 2Cu2+ → Sn4+ + 2Cu+.

18: Determine the oxidation number of sulfur in each compound: SO2, SO3, and H2SO4.

19: Considering the reaction: Fe2O3 + 3CO → 2Fe + 3CO2, what is the change in oxidation number for iron (Fe)?

20: Predict the formula of the ionic compound formed between magnesium (Mg2+) and nitrate (NO3-).

21: Analyze the following statement: "The sum of oxidation numbers in a polyatomic ion is always equal to the charge on the ion." Explain why this statement is true.

22: In the balanced equation: Zn + 2HCl → ZnCl2 + H2, what is the role of hydrochloric acid (HCl) in the reaction?

23: Describe a real-world example of a redox reaction and explain its significance.

24: Define the term "corrosion" and provide examples of methods used to prevent corrosion, mentioning both barrier methods and sacrificial protection.

25: Differentiate between the oxidation number of a monatomic ion and the oxidation number of an element in a compound. Provide an example to illustrate the distinction.

26: How can one recognize a redox reaction by observing color changes when using acidified aqueous potassium manganate(VII) to potassium iodide? Explain the significance of these color changes.

27: What is the oxidation number of elements in their free state?

28: Explain how to derive the formula of an ionic compound from ionic charges and oxidation numbers.

29: How do you recognize a redox reaction involving aqueous potassium manganate (VII)?

30: Define the oxidation number of a monatomic ion.