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d- and f-Block Elements

JEE Main 2024 (Online) 4th April Morning ShiftNumericalMedium📈 Topic in 19% papers+4
Ques. 1JEE Main 2024, 4 April (Morning Shift)

Consider the following reaction MnO2 + KOH + O2 A + H2O. Product 'A' in neutral or acidic medium disproportionate to give products 'B' and 'C' along with water. The sum of spin-only magnetic moment values of B and C is BM. (nearest integer) (Given atomic number of Mn is 25)

Answer

4

Solution

2MnO2 + 4KOH + O2 2K2MnO4 + 2H2O ⇒ A = K2MnO4

3MnO42- + 4H+ 2MnO4- + MnO2 + 2H2O ⇒ B, C = KMnO4, MnO2

KMnO4: Mn7+, 3d0 ⇒ n = 0 ⇒ μ = 0

MnO2: Mn4+, 3d3 ⇒ n = 3 ⇒ = 3(3 + 2) = 3.87 BM

∴ Sum = 0 + 3.87 ≈ 4 BM

Answer: 4

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Ques. 2JEE Main 2024, 4 April (Evening Shift)

A first row transition metal in its +2 oxidation state has a spin-only magnetic moment value of 3.86 BM. The atomic number of the metal is

  1. 22
  2. 23
  3. 26
  4. 25
Ques. 3JEE Main 2024, 4 April (Evening Shift)

A first row transition metal with highest enthalpy of atomisation, upon reaction with oxygen at high temperature forms oxides of formula M2On (where n = 3, 4, 5). The 'spin-only' magnetic moment value of the amphoteric oxide from the above oxides is BM (near integer) (Given atomic number: Sc : 21, Ti : 22, V : 23, Cr : 24, Mn : 25, Fe : 26, Co : 27, Ni : 28, Cu : 29, Zn : 30)

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

In acidic medium, K2Cr2O7 shows oxidising action as represented in the half reaction: Cr2O72- + XH+ + Ye 2A + ZH2O X, Y, Z and A are respectively :

  1. 14, 7, 6 and Cr3+
  2. 14, 6, 7 and Cr3+
  3. 8, 4, 6 and Cr2O3
  4. 8, 6, 4 and Cr2O3
Ques. 5JEE Main 2024, 1 February (Evening Shift)

The transition metal having highest 3rd ionisation enthalpy is :

  1. Mn
  2. Fe
  3. Cr
  4. V
Ques. 6JEE Main 2024, 1 February (Evening Shift)

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below :

  1. (A) is true but (R) is false
  2. Both (A) and (R) are true and (R) is the correct explanation of (A)
  3. Both (A) and (R) are true but (R) is not the correct explanation of (A)
  4. (A) is false but (R) is true
Ques. 7JEE Main 2024, 1 February (Evening Shift)

Which of the following compounds show colour due to d-d transition?

  1. K2Cr2O7
  2. CuSO4 5H2O
  3. KMnO4
  4. K2CrO4
Ques. 8JEE Main 2024, 31 January (Morning Shift)

Identify correct statements from below: Choose the correct answer from the options given below:

  1. B, D, E only
  2. A, B, C only
  3. A, D, E only
  4. B, C, D only
Ques. 9JEE Main 2024, 31 January (Morning Shift)

The metals that are employed in the battery industries are Choose the correct answer from the options given below:

  1. A, B, C, D and E
  2. A, B, C and D only
  3. B, D and E only
  4. B, C and E only
Ques. 10JEE Main 2024, 31 January (Evening Shift)

Choose the correct statements from the following Choose the correct answer from the options given below :

  1. A, B and D only
  2. A, B and C only
  3. A and C only
  4. B and C only
Ques. 11JEE Main 2024, 31 January (Evening Shift)

In the reaction of potassium dichromate, potassium chloride and sulfuric acid (conc.), the oxidation state of the chromium in the product is (+) .

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