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Redox Reactions

JEE Main 2024 (Online) 8th April Morning ShiftMCQEasy📈 Topic in 3% papers+4−1
Ques. 1JEE Main 2024, 8 April (Morning Shift)

Thiosulphate reacts differently with iodine and bromine in the reactions given below: 2S2O32- + I2 S4O62- + 2I- S2O32- + 5Br2 + 5H2O 2SO42- + 4Br- + 10H+ Which of the following statements justifies the above dual behaviour of thiosulphate?

  1. Thiosulphate undergoes oxidation by bromine and reduction by iodine in these reactions
  2. Bromine is a weaker oxidant than iodine
  3. Bromine is a stronger oxidant than iodine
  4. Bromine undergoes oxidation and iodine undergoes reduction in these reactions

Answer

(3) Bromine is a stronger oxidant than iodine

Solution

Oxidation number of S:

with I2: S2O32- (+2) → S4O62- (+2.5)

with Br2: S2O32- (+2) → SO42- (+6)

Bromine takes S to a much higher oxidation state, so bromine is the stronger oxidant.

E (Br2/Br-) = 1.09 V > E (I2/I-) = 0.54 V

(1): thiosulphate is oxidised in both reactions, so (1) is wrong

(2): it states the reverse of the fact, so (2) is wrong

(4): both Br2 and I2 are reduced (to Br- and I-), so (4) is wrong

Answer: (3)

Keep practising — Redox Reactions

Ques. 2JEE Main 2024, 6 April (Evening Shift)

Match List I with List II. Choose the correct answer from the options given below :

  1. A-IV, B-I, C-II, D-III
  2. A-I, B-II, C-III, D-IV
  3. A-II, B-III, C-IV, D-I
  4. A-III, B-II, C-I, D-IV
Ques. 3JEE Main 2024, 4 April (Morning Shift)

Only 2 mL of KMnO4 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 KMnO4 solution should be M.

Ques. 4JEE Main 2024, 1 February (Morning Shift)

Which of the following reactions are disproportionation reactions? Choose the correct answer from the options given below :

  1. (A), (B)
  2. (A), (D)
  3. (B), (C), (D)
  4. (A), (B), (C)
Ques. 5JEE Main 2024, 1 February (Morning Shift)

The lowest oxidation number of an atom in a compound A2B is -2 . The number of electrons in its valence shell is .

Ques. 6JEE Main 2024, 31 January (Evening Shift)

Given below are two statements: In the light of the above statements, choose the most appropriate answer from the options given below :

  1. Statement I is correct but statement II is incorrect
  2. Both statement I and statement II are incorrect
  3. Statement I is incorrect but statement II is correct
  4. Both statement I and statement II are correct
Ques. 7JEE Main 2024, 31 January (Evening Shift)

Number of moles of H+ ions required by 1 mole of MnO4- to oxidise oxalate ion to CO2 is .

Ques. 8JEE Main 2024, 30 January (Morning Shift)

2MnO4- + bI- + cH2O xI2 + yMnO2 + zOH- If the above equation is balanced with integer coefficients, the value of z is .

Ques. 9JEE Main 2024, 30 January (Evening Shift)

Total number of species from the following which can undergo disproportionation reaction is . H2O2, ClO3-, P4, Cl2, Ag, Cu+1, F2, NO2, K+

Ques. 10JEE Main 2024, 29 January (Morning Shift)

Chlorine undergoes disproportionation in alkaline medium as shown below : aCl2(g) + bOH-(aq) cClO-(aq) + dCl-(aq) + eH2O(l) The values of a, b, c and d in a balanced redox reaction are respectively :

  1. 3, 4, 4 and 2
  2. 1, 2, 1 and 1
  3. 2, 4, 1 and 3
  4. 2, 2, 1 and 3
Ques. 11JEE Main 2024, 27 January (Morning Shift)

From the given list, the number of compounds with +4 oxidation state of Sulphur . SO3, H2SO3, SOCl2, SF4, BaSO4, H2S2O7

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