Redox Reactions PYQs Set 3 (PDF)

Set 3 of 6 · Questions 61-90 of 163

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Redox Reactions · Set 3 (Q61-90)
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61. $3 ClO_{(aq)}^{-} ⟶ ClO 3^{-} + 2 Cl^{-} is an example of$ (1) $oxidation reaction$ (2) $reduction reaction$ (3) $disproportionation reaction$ (4) $decomposition reaction.$ 62. $Amongs the following which is redox reaction?$ (1) $N_{2} + O_{2} 2000 K 2NO$ (2) $Formation of O_{3} from O_{2}$ (3) $Reaction between NaOH and H_{2} S O_{4}$ (4) $Reaction between AgN O_{3} and NaCl$ 63. $Which of the following is only a redox reaction but not a disproportionation reaction?$ (1) $4 H_{3} PO_{3} \to 3 H_{3} PO_{4} + PH_{3}$ (2) $2 H_{2} O_{2} \to 2 H_{2} O + O_{2}$ (3) $P_{4} + 3 NaOH + 3 H_{2} O \to 3 NaH_{2} PO_{2} + PH_{3}$ (4) $P_{4} + 8 SOCl_{2} \to 4 PCl_{3} + 2 S_{2} Cl_{2} + 4 SO_{2}$ 64. $Identify the oxidation states of Mn, when MnO_{4}^{2 -} ion undergoes disproportionation reaction under acidic medium.$ (1) $+ 2, + 7$ (2) $+ 2, + 5$ (3) $+ 4, + 4$ (4) $+ 7, + 4$ 65. $What is the oxidation number of Pt in PtCl_{6}^{2 -} ?$ (1) $+6$ (2) $+4$ (3) $-4$ (4) $-6$ 66. $What are x, y and z respectively in the following reaction? xFe^{2 +} (aq) + yH^{+} (aq) + zCr_{2} O_{7}^{2 -} (aq) \to \frac{y}{2} H_{2} O (l) + xFe^{3 +} (aq) + 2 zCr^{3 +} (aq)$ (1) $14, 1, 6$ (2) $14, 6, 1$ (3) $6, 1, 14$ (4) $6, 14, 1$ 67. $Which of the following represents disproportionation of potassium chlorate?$ (1) $2 KClO_{3} ⟶ 2 KCl + 3 O_{2}$ (2) $3 KClO_{3} ⟶ 2 KClO_{2} + KClO_{3}$ (3) $4 KClO_{3} ⟶ 3 KClO_{4} + KCl$ (4) $None of the above$ 68. $When compared to Δ G^{\circ} for the formation of Al_{2} O_{3}, the Δ G^{\circ} for the formation of Cr_{2} O_{3} is$ (1) $same$ (2) $unpredicted$ (3) $higher$ (4) $lower.$ 69. $Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R Assertion A : Permanganate titrations are not performed in presence of hydrochloric acid. Reason R : Chlorine is formed as a consequence of oxidation of hydrochloric acid. In the light of the above statements, choose the correct answer from the options given below$ (1) $Both A and R are true and R is the correct explanation of A$ (2) $Both A and R are true but R is NOT the correct explanation of A$ (3) $A is true but R is false$ (4) $A is false but R is true$ 70. $One mole of Cl_{2} (g) was passed into 2 L of cold 2 M KOH solution. After the reaction, the concentrations of Cl^{-}, ClO^{-} and OH^{-} are respectively (assume volume remains constant)$ (1) $0.5 M, 0.5 M, 1 M$ (2) $0.75 M, 0.75 M, 1 M$ (3) $0.5 M, 0.5 M, 0.5 M$ (4) $1 M, 1 M, 1 M$ 71. $The oxidation state of Fe in the brown ring complex (Fe (H_{2} O)_{5} NO^{2}] SO_{4}) is$ (1) $0$ (2) $+2$ (3) $+1$ (4) $+3$ 72. $Which of the following reactions are disproportionation reactions? (A) Cu^{+} \to Cu^{2 +} + Cu (B) 3 MnO_{4}^{2 -} + 4 H^{+} \to 2 MnO_{4}^{-} + MnO_{2} + 2 H_{2} O (C) 2 KMnO_{4} \to K_{2} MnO_{4} + MnO_{2} + O_{2} (D) 2 MnO_{4}^{-} + 3 Mn^{2 +} + 2 H_{2} O \to 5 MnO_{2} + 4 H^{+} Choose the correct answer from the options given below:$ (1) $(A), (B)$ (2) $(B), (C), (D)$ (3) $(A), (B), (C)$ (4) $(A), (D)$ 73. $Balance the following equation by choosing the correct option. x KNO_{3} + y C_{12} H_{22} O_{11} ⟶ p N_{2} + q CO_{2} + r H_{2} O + s K_{2} CO_{3} x y p q r s$ (1) $36 55 24 24 5 48$ (2) $48 5 24 36 55 24$ (3) $24 24 36 55 48 5$ (4) $24 48 36 4 5 55$ 74. $In the ionic equation, BiO_{3}^{-} + 6 H^{+} + x e^{-} \to Bi^{3 +} + 3 H_{2} O, the values of x is$ (1) $6$ (2) $2$ (3) $4$ (4) $3$ 75. $Number ofmoles of M n O_{4}^{-} required to oxidize one mole of ferrous oxalate completely in acidic medium will be$ (1) $7.5 moles$ (2) $0.2 moles$ (3) $0.6 moles$ (4) $0.4 moles.$ 76. $What is the change in oxidation number of carbon in the following reaction? CH_{4} (g) + 4 Cl_{2} (g) \to CCl_{4} (l) + 4 HCl (g)$ (1) $0 to +4$ (2) $-4 to +4$ (3) $0 to -4$ (4) $+4 to +4$ 77. $What is the oxidation number of gold in the complex (AuCl_{4})^{1 -} ?$ (1) $+4$ (2) $+3$ (3) $+2$ (4) $+1$ 78. $The pair of compounds that can exist together is$ (1) $F e C l_{3}, S n C l_{2}$ (2) $H g C l_{2}, S n C l_{2}$ (3) $F e C l_{2}, S n C l_{2}$ (4) $F e C l_{3}, KI$ 79. $On balancing the given redox reaction, aCr_{2} O_{7}^{(2 -)} + bSO_{3}^{(2 -)} (aq) + cH^{+} (aq) \to 2 aCr^{3 +} (aq) + bSO_{4}^{2 -} (aq) + c /2 H_{2} O (l) the coefficients a, b and c are found to be, respectively:$ (1) $8, 1, 3$ (2) $1, 3, 8$ (3) $3, 8, 1$ (4) $1, 8, 3$ 80. $Thiosulphate reacts differently with iodine and bromine in the reactions given below: 2 S_{2} O_{3}^{2 -} + I_{2} \to S_{4} O_{6}^{2 -} + 2 I^{-} S_{2} O_{3}^{2 -} + 5 Br_{2} + 5 H_{2} O \to 2 SO_{4}^{2 -} + 4 Br^{-} + 10 H^{+} Which of the following statement justifies the above dual behaviour of thiosulphate?$ (1) $Bromine is a stronger oxidant than iodine$ (2) $Thiosulphate undergoes oxidation by bromine and reduction by iodine in these reaction$ (3) $Bromine is a weaker oxidant than iodine$ (4) $Bromine undergoes oxidation and iodine undergoes reduction in these reactions$ 81. $The oxidation states of 'P' in H_{4} P_{2} O_{7}, H_{4} P_{2} O_{5} and, H_{4} P_{2} O_{6}, respectively, are :$ (1) $7,5 and 6$ (2) $5,4 and 3$ (3) $5,3 and 4$ (4) $6,4 and 5$ 82. $In which of the following compounds, an element exhibits two different oxidation states?$ (1) $N_{2} H_{4}$ (2) $NH_{2} CONH_{2}$ (3) $N_{3} H$ (4) $NH_{4} NO_{3}$ 83. $20 mL of 0.02 M K_{2} C r_{2} O_{7} solution is used for the titration of 10 mL of F e^{2 +} solution in the acidic medium.The molarity of F e^{2 +} solution is______x 1 0^{- 2} M.(Nearest Integer)$ 84. $0.4 g mixture of NaOH, N a_{2} C O_{3} and some inert impurities was first titrated with \frac{N}{10} HCL using phenolphthalein as an indicator, 17.5 mL of HCl was required at the end point. After this methyl orange wasadded and titrated. 1.5 mL of same HCl was required for the next end point. The weight percentage of Na_{2} CO_{3} in the mixture is ____ (Rounded-off to the nearest integer)$ 85. $Consider titration of NaOH solution versus 1.25 M oxalic acid solution. At the end point following burette readings were obtained. (i) 4.5 ml (ii) 4.5 ml (iii) 4.4 ml (iv) 4.4 ml (v) 4.4 ml If the volume of oxalic acid taken was 10 mL, then the molarity of the NaOH solution is ____ M. (Rounded off to the nearest integer)$ 86. $Consider the following equations: 2 Fe^{2 +} + H_{2} O_{2} \to xA + yB (in basic medium) 2 MnO_{4}^{-} + 6 H^{+} + 5 H_{2} O_{2} \to x^{’} C + y^{’} D + z^{’} E (in acidic medium) The sum of the stoichiometric coefficients x, y,, x^{’}, y^{’} and z^{’} for products A, B, C, D and E,respectively, is$ 87. $500 mL of 1.2 M KI solution is mixed with 500 mL of 0.2 MKMnO_{4} solution in basic medium. The liberated iodine was titrated with standard 0.1 MNa_{2} S_{2} O_{3} solution in the presence of starch indicator till the blue color disappeared. The volume (in L) of Na_{2} S_{2} O_{3} consumed is____(Nearest integer)$ 88. $The formula of a gaseous hydrocarbon which requires 6 times of its own volume of O_{2} for complete oxidationand produces 4 times its own volume of CO_{2} is C_{x} H_{y} . The value of y is ____.$ 89. $(A) \to NaOH (B) \to + H_{2} O_{2} dil . H_{2} SO_{4} (c) NaCI \to Conc . H_{2} SO_{4} K_{2} Cr_{2} O_{7} (s) Determine total number of atoms in per unit formula of (A), (B) & (C)$ 90. $Only 2 mL of KMnO_{4} solution of unknown molarity is required to reach the end point of a titration of 20 mL of oxalic acid (2M) in acidic medium. The molarity of KMnO_{4} solution should be M.$