Oxidation and reduction, oxidation number
- Consider the following compounds : KO_2, H_2O_2 and H_2SO_4.The oxidation states of the underlined elements in them are, respectively, Answer: 1. +1, -1, and +6 Key idea: assign oxidation states from known charges. KO₂ is potassium superoxide, K^+ and O₂^- : K = +1. H₂O₂ is... 1
- Which reaction is NOT a redox reaction? Answer: 1. BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl Key idea: a redox reaction has a change in oxidation numbers. BaCl₂+Na₂SO₄→ BaSO₄+2NaCl is a doubl... 1
- Which of the following reactions is the metal displacement reaction ? Choose the right option. Answer: 2. Cr₂O₃ + 2Al xrightarrowΔ Al₂O₃ + 2Cr Key idea: a metal displacement reaction is one where a more reactive metal displaces a less... 1
- What is the change in oxidation number of carbon in the following reaction ?CH_4(g) + 4Cl_2(g) → CCl_4(l) + 4HCl(g) Answer: 3. - 4 to +4 Find carbon's oxidation number on each side. In CH₄ : x+4(+1)=0 , so x=-4 . In CCl₄ : x+4(-1)=0 , so x=+4 . The change... 1
- Which of the following reactions are disproportionation reaction ?(a) 2Cu^+ → Cu^2+ + Cu^0(b) 3MnO_4^2- + 4H^+ → 2MnO_4^- + MnO_2 + 2H_2O(c) 2KMnO_4 Δ K_2MnO_4 + MnO_2 + O_2(d) 2MnO_4^- + 3Mn^2+ + 2H_2O → 5MnO_2 + 4H^Select the correct option from th… Answer: 1. (a) and (b) only A disproportionation reaction is one in which the same species is both oxidised and reduced. (a) mathrmCu^+ → Cu... 1
- The correct order of N-compounds in its decreasing order of oxidation states is Answer: 1. HNO ₃ , NO, N ₂ , NH ₄ Cl Find the oxidation state of N in each compound. HNO₃ : +5 NO: +2 N₂ : 0 NH₄Cl : -3 The decreasing order... 1