Oxidation and Reduction — Redox
Chemistry · 50 practice questions
Oxidation as addition of oxygen or removal of hydrogen; reduction as removal of oxygen or addition of hydrogen; oxidation and reduction in terms of electron transfer; use of oxidation numbers, including balancing simple equations; IUPAC nomenclature of inorganic compounds using oxidation number; tests for oxidizing and reducing agents.
- Identify the various forms of expressing oxidation and reduction.
- Classify chemical reactions as oxidation or reduction and balance redox equations.
- Deduce the oxidation number of chemical species and compute electron transfer in redox reactions.
- Identify redox species and distinguish oxidizing from reducing agents.
- Apply oxidation numbers in naming inorganic compounds and relate reagents to their oxidizing/reducing abilities.
Try a few questions
- Practice question 1
When balancing a redox equation using oxidation numbers, the total increase in oxidation number (oxidation) must
- A.equal the total decrease in oxidation number (reduction)
- B.always exceed the total decrease in oxidation number
- C.always be less than the total decrease in oxidation number
- D.have no defined relationship to the total decrease in oxidation number
Show the answer
A. equal the total decrease in oxidation number (reduction)
Electrons lost in oxidation must exactly match electrons gained in reduction, keeping the equation properly balanced.
- Practice question 2
Common laboratory oxidizing agents mainly include
- A.concentrated trioxonitrate(V) acid, potassium tetraoxomanganate(VII), and potassium dichromate(VI)
- B.hydrogen gas, sulphur(IV) oxide, and zinc metal
- C.sodium chloride and calcium trioxocarbonate(IV)
- D.distilled water and ethanol
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A. concentrated trioxonitrate(V) acid, potassium tetraoxomanganate(VII), and potassium dichromate(VI)
These well-known reagents are all readily available substances that act as strong electron acceptors.
- Practice question 3
In the reaction CuO + H₂ → Cu + H₂O, hydrogen gas acts as a
- A.oxidizing agent, since it is itself reduced while oxidizing the copper(II) oxide
- B.catalyst, remaining chemically unchanged throughout the reaction
- C.species with no redox role in this particular reaction
- D.reducing agent, since it is itself oxidized while reducing the copper(II) oxide
Show the answer
D. reducing agent, since it is itself oxidized while reducing the copper(II) oxide
Hydrogen removes oxygen from CuO (reducing it to copper) while itself being oxidized to water.
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