📘Chemistry common questions about Redox Reactions & Oxidation States:
1. Which of the following is a defining characteristic of ALL redox reactions? a) Formation of a precipitate
b) Transfer of protons (H⁺ ions)
c) Transfer of electrons
d) Release of heat (exothermic reaction)
Answer: c) Transfer of electrons2. In the following reaction, which species is being oxidized? 2 Ag⁺(aq) + Cu(s) → 2 Ag(s) + Cu²⁺(aq)
a) Ag⁺
b) Cu
c) Ag
d) Cu²⁺
Answer: b) Cu (Loses electrons, oxidation number increases)
3. What is the oxidation state of sulfur (S) in H₂SO₄? a) +2
b) +4
c) +6
d) -2
Answer: c) +6 4. Which of the following is NOT a possible oxidation state of chlorine (Cl)? a) -1
b) +1
c) +3
d) +6
Answer: d) +6 (Chlorine can have oxidation states from -1 to +7, but not +6)
5. In a balanced half-reaction, what is used to balance the charges? a) H₂O
b) H⁺ ions
c) Electrons (e⁻)
d) All of the above
Answer: c) Electrons (e⁻) 6. A reducing agent is a species that: a) Loses electrons and is reduced.
b) Gains electrons and is reduced.
c) Loses electrons and is oxidized.
d) Gains electrons and is oxidized.
Answer: c) Loses electrons and is oxidized. 7. In the compound Na₂O₂, what is the oxidation state of oxygen (O)? a) -2
b) -1
c) 0
d) +1
Answer: b) -1 (This is a peroxide)
8. Disproportionation is a type of redox reaction in which: a) The same element is both oxidized and reduced.
b) Two different elements are oxidized.
c) No electrons are transferred.
d) The reaction is always endothermic.
Answer: a) The same element is both oxidized and reduced.9. What is the oxidation state of manganese (Mn) in the permanganate ion (MnO₄⁻)? a) +2
b) +4
c) +7
d) -1
Answer: c) +7 10. Which of the following statements is TRUE about oxidation states? a) They always represent the actual charges on atoms in a compound.
b) They are used to keep track of electron transfer in chemical reactions.
c) They are always positive whole numbers.
d) They are not applicable to covalent compounds.
Answer: b) They are used to keep track of electron transfer in chemical reactions. Credit;ENTRANCE TRICKS