Ncert-class 11-chemistry – unit 7- Redox Reactions Welcome to your Ncert-class 11-chemistry - unit 7- Redox Reactions 1. The oxidation number of oxygen in$$KO_{3},Na_{2}O_{2}$$ is 0,1 -0.33,-1 3,2 1,0 None 2. Write balanced equations for the half reactions and calculate the reduction potentials at 25ºC for the following half cells : $$Cl^{-}(1.2M)|Cl_{2}(g,3.6atm)|PtE^{\cdot} =1.36V$$ 1.372V 1.363V 1.358V 1.342V None 3. When a piece of sodium metal is dropped in water, hydrogen gas evolved because: sodium loses electrons and is oxidised while water in reduced water is oxidised and acts as a reducing agent sodium is reduced and acts as an oxidising agent water loses electrons and is oxidised to hydrogen None 4. In acid medium, the standard reduction potential of 𝑁𝑂converted to 𝑁2𝑂 is 1.59 𝑉. Its standard potential in alkaline medium would be: -0.764V -1.59V 0.062V 0.764V None 5. The oxidation state of phosphorus is maximum in_________. $$ diphosphine (P_{2}H_{4})$$ $$metaphosphoric acid (𝐻PO_{3})$$ $$phospine (𝑃𝐻_{3})$$ $$phosphorus acid(𝐻_{3}PO_{3})$$ None 6. Which of the following statements is wrong? Oxidation number of oxygen is +1 in peroxides Oxidation number of oxygen is − 2 in most of its compounds Oxidation number of oxygen is − 1 / 2 super oxides Oxidation number of oxygen is + 2 in oxygen difluoride None 7. Find the oxidation number of elements in each case :S in Na_{2}S_{2}O_{3},S_{4}, S_{8}, Na_{2}S_{2}O_{7} +1,0,+1,+6 None +1,0,0,+4 +2,0,0,+6 None 8. What will be the reduction potential for the following half-cell reaction at 298K?(Given \([Ag^{+}])\=0.1M and E°cell =+0.80V) −0.741V 0.741V −0.80V 0.80V None 9. Oxidation number of Cl in 𝐾𝐶𝑙𝑂3 +5 -1 -5 +1 None 10. Oxidation number of Cr is +5 in : $$K_{3}CrO_{8}$$ $$(NH_{3})_{3}CrO_{4}$$ $$[Cr(NH_{3})_{5}(H_{2}O)]Cl_{3}$$ $$K_{2}CrO_{4}$$ None 11. Which of the following species has an atom with +6 oxidation state? $$Cr(CN)_{6}^{3-}$$ $$CrO_{2}Cl_{2}$$ $$NiF_{6}^{2-}$$ $$MnO_{4}^{-} $$ None 12. In the conversion of $$Br_{2} to BrO_{3}^{-}$$ , the oxidation state of Br changes from: 0 to -3 0 to +5 +2 to +5 +1 to +5 None 13. Oxidation state of nitrogen is not an integer in: $$hydrazine (N_{2}H_{4})$$ $$hydroxyl amine (NH_{2}OH)$$ $$hydrazoic acid (N_{3}H)$$ $$ ammonia(NH_{3})$$ None 14. The oxidation state of A,B and C in compaund are -2, +5, and -2, respectively. the compound is ? $$A_2(BC)_{3}$$ $$A_2(BC)_{5}$$ $$A_3(BC)_{2}$$ None 15. Which of the following is a redox reaction? Reaction of \(H_{2}SO_{4})\ with NaOH Formation of oxides of nitrogen from nitrogen and oxygen by lightening. In atmosphere , formation of 𝑂3 from 𝑂2 by lightening Evaporation of 𝐻 2 𝑂 None 16. What is the oxidation number of 𝑀𝑛 in$$KMnO_{4}, K_{2}MnO_{4}, MnSO_{4}, MnO, Mn_{3}O_{4}$$ respectively None of these +4,+6,+2,+4,+8/3 +7,+6,+2,+3,+8/3 + 7 , + 6 , + 2 , + 4 , + 8/3 None 17. The oxidation number of all the elements in the given compound is: Ethane \((C_{2}H_{6}))\ 3,-1 +3,+1 4,+1 3,0 None 18. Two half-cells have potentials −0.44 and 0.799 volt respectively. These two are coupled to make a galvanic cell. Which of the following will be true? Electrode of half-cell potential − 0.44 𝑉 will act as cathode Electrode of half-cell potential − 0.44 𝑉 will act as a positive terminal Electrode of half-cell potential − 0.44 𝑉 will act as anode Electrode of half-cell potential 0.799 𝑉 will act as anode None 19. The oxidation state of the metal atom is zero in: ferrous sulphate rust ferric sulphate iron carbonyl None 20. Alizarin belongs to the class of Reactive dye Mordant dye Basic dye Vat dyes None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
