What is a redox reaction? Solution: A redox reaction is a chemical reaction where oxidation and reduction occur simultaneously. Oxidation involves the loss of electrons, and reduction involves the gain of electrons.
- In the reaction 2H₂ + O₂ → 2H₂O, which species is reduced? Solution: O₂ is reduced because it gains electrons from H₂.
- What is the oxidizing agent in the reaction 2Na + Cl₂ → 2NaCl? Solution: Cl₂ is the oxidizing agent because it accepts electrons from Na.
- In the reaction 2Fe + 3O₂ → 2Fe₂O₃, which species is oxidized? Solution: Fe is oxidized because it loses electrons to O₂.
- What is the reducing agent in the reaction Zn + Cu²⁺ → Zn²⁺ + Cu? Solution: Zn is the reducing agent because it donates electrons to Cu²⁺.
- In the reaction 2Mg + O₂ → 2MgO, what is the oxidation state of oxygen before and after the reaction? Solution: Before the reaction, the oxidation state of oxygen is 0 (in O₂) and after the reaction, it is -2 (in MgO).
- What is the oxidation state of sulfur in H₂SO₄? Solution: The oxidation state of sulfur in H₂SO₄ is +6.
- Is the decomposition of water into hydrogen and oxygen gas a redox reaction? Solution: Yes, the decomposition of water into hydrogen and oxygen gas is a redox reaction. Oxygen is reduced and hydrogen is oxidized.
- In the reaction 2H₂O₂ → 2H₂O + O₂, is H₂O₂ acting as the oxidizing agent or the reducing agent? Solution: H₂O₂ is acting as both the oxidizing agent (since it gains electrons to form H₂O) and the reducing agent (since it loses electrons to form O₂).
- What happens to the oxidation number of an element in a redox reaction when it is reduced? Solution: When an element is reduced, its oxidation number decreases.
- What is the oxidation state of carbon in CO₂? Solution: The oxidation state of carbon in CO₂ is +4.
- What is the balanced half-reaction for the reduction of NO₃⁻ to NO? Solution: The balanced half-reaction for the reduction of NO₃⁻ to NO is: NO₃⁻ + 2H⁺ + e⁻ → NO + H₂O
- What is the oxidation state of chromium in Cr₂O₇²⁻? Solution: The oxidation state of chromium in Cr₂O₇²⁻ is +6.
- Is the reaction of zinc with hydrochloric acid a redox reaction? Solution: Yes, the reaction of zinc with hydrochloric acid is a redox reaction. Zinc is oxidized and hydrogen is reduced.
- How does the concept of oxidation states help identify redox reactions? Solution: The concept of oxidation states helps identify redox reactions by showing how the charge or oxidation states of atoms change during the reaction. If the oxidation state of an atom changes during the reaction, a redox reaction has occurred.
- Is combustion a type of redox reaction? Solution: Yes, combustion is a type of redox reaction. In a combustion reaction, a substance combines with oxygen, which is reduced, while the substance being combusted is oxidized.
- In the reaction 2Al + 3Cu²⁺ → 2Al³⁺ + 3Cu, what is the oxidation state of Al before and after the reaction? Solution: Before the reaction, the oxidation state of Al is 0 (in Al) and after the reaction, it is +3 (in Al³⁺).
- What is disproportionation in the context of redox reactions? Solution: Disproportionation in the context of redox reactions is a process where a single species is simultaneously oxidized and reduced.
- In the reaction 2H₂ + O₂ → 2H₂O, what is the oxidation state of hydrogen before and after the reaction? Solution: Before the reaction, the oxidation state of hydrogen is 0 (in H₂) and after the reaction, it is +1 (in H₂O).
Can a single atom undergo both oxidation and reduction in a redox reaction? Solution: Yes, a single atom can undergo both oxidation and reduction in a process known as disproportionation. An example is the decomposition of hydrogen peroxide (H₂O₂), where oxygen is both reduced and oxidized.
