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d- and f-Block Elements

JEE Main 2024 (Online) 31st January Evening ShiftNumericalEasy📈 Topic in 19% papers+4
Ques. 1JEE 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 (+) .

Answer

6

Solution

Chromyl chloride test:

K2Cr2O7 + 4KCl + 6H2SO4

2CrO2Cl2 + 6KHSO4 + 3H2O

In CrO2Cl2: x + 2(−2) + 2(−1) = 0 ⇒ x = +6

∵ Cr stays +6 (no redox; same as in K2Cr2O7)

Answer: 6

Keep practising — d- and f-Block Elements

Ques. 2JEE Main 2024, 30 January (Morning Shift)

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

  1. A-III, B-IV, C-I, D-II
  2. A-I, B-II, C-III, D-IV
  3. A-IV, B-III, C-I, D-II
  4. A-II, B-I, C-IV, D-III
Ques. 3JEE Main 2024, 30 January (Morning Shift)

Diamagnetic Lanthanoid ions are :

  1. La3+ \& Ce4+
  2. Nd3+ \& Ce4+
  3. Lu3+ \& Eu3+
  4. Nd3+ \& Eu3+
Ques. 4JEE Main 2024, 30 January (Evening Shift)

A and B formed in the following reactions are: CrO2Cl2 + 4NaOH A + 2NaCl + 2H2O, A + 2HCl + 2H2O2 B + 3H2O

  1. A = Na2Cr2O7, B = CrO5
  2. A = Na2CrO4, B = CrO5
  3. A = Na2Cr2O4, B = CrO4
  4. A = Na2Cr2O7, B = CrO3
Ques. 5JEE Main 2024, 30 January (Evening Shift)

Alkaline oxidative fusion of MnO2 gives "A" which on electrolytic oxidation in alkaline solution produces B. A and B respectively are

  1. Mn2O3 and MnO42-
  2. Mn2O7 and MnO4-
  3. MnO42- and MnO4-
  4. MnO42- and Mn2O7
Ques. 6JEE Main 2024, 30 January (Evening Shift)

The orange colour of K2Cr2O7 and purple colour of KMnO4 is due to

  1. Charge transfer transition in both.
  2. d d transitions in KMnO4 and charge transfer transitions in K2Cr2O7.
  3. d d transitions in both
  4. d d transitions in K2Cr2O7 and charge transfer transitions in KMnO4.
Ques. 7JEE Main 2024, 29 January (Morning Shift)

KMnO4 decomposes on heating at 513 K to form O2 along with

  1. K2MnO4 & Mn
  2. MnO2 & K2O2
  3. K2MnO4 & MnO2
  4. Mn & KO2
Ques. 8JEE Main 2024, 29 January (Morning Shift)

In alkaline medium, MnO4- oxidises I- to

  1. I2
  2. IO3-
  3. IO-
  4. IO4-
Ques. 9JEE Main 2024, 29 January (Evening Shift)

Which of the following acts as a strong reducing agent? (Atomic number: Ce = 58, Eu = 63, Gd = 64, Lu = 71)

  1. Eu2+
  2. Gd3+
  3. Lu3+
  4. Ce4+
Ques. 10JEE Main 2024, 29 January (Evening Shift)

Which of the following statements are correct about Zn, Cd and Hg? Choose the most appropriate from the options given below:

  1. C, D only
  2. B, C only
  3. A, D only
  4. B, D only
Ques. 11JEE Main 2024, 27 January (Morning Shift)

Which of the following electronic configuration would be associated with the highest magnetic moment?

  1. [Ar]3d7
  2. [Ar]3d8
  3. [Ar]3d3
  4. [Ar]3d6

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