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d- and f-Block Elements

JEE Main 2025 (Online) 28th January Evening ShiftMCQEasy📈 Topic in 14% papers+4−1
Ques. 1JEE Main 2025, 28 January (Evening Shift)

The amphoteric oxide among V2O3, V2O4 and V2O5, upon reaction with alkali leads to formation of an oxide anion. The oxidation state of V in the oxide anion is :

  1. + 4
  2. + 5
  3. + 3
  4. + 7

Answer

(2) + 5

Solution

Acidic character of oxides of a transition metal increases with oxidation state: V2O3 (+3) is basic, V2O4 (+4) is less basic, and V2O5 (+5) is amphoteric, though mainly acidic (NCERT).

With alkali, V2O5 gives vanadate ions:

V2O5 + 6OH- 2VO43- + 3H2O

In VO43-: x + 4(-2) = -3 x = +5

(the oxidation state does not change in this acid–base reaction).

Answer: (2)

Keep practising — d- and f-Block Elements

Ques. 2JEE Main 2025, 28 January (Evening Shift)

The spin only magnetic moment ( ) value (B.M.) of the compound with the strongest oxidising power among Mn2O3, TiO and VO is B.M. (Nearest integer).

Ques. 3JEE Main 2025, 24 January (Morning Shift)

Preparation of potassium permanganate from MnO2 involves two step process in which the 1st step is a reaction with KOH and KNO3 to produce

  1. K3MnO4
  2. K4[Mn(OH)6]
  3. K2MnO4
  4. KMnO4
Ques. 4JEE Main 2025, 24 January (Morning Shift)

Which of the following ions is the strongest oxidizing agent? (Atomic Number of Ce = 58, Eu = 63, Tb = 65, Lu = 71)

  1. Lu3+
  2. Eu2+
  3. Tb4+
  4. Ce3+
Ques. 5JEE Main 2025, 24 January (Evening Shift)

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

  1. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
  2. (A)-(II), (B)-(IV), (C)-(I), (D)-(III)
  3. (A)-(III), (B)-(I), (C)-(II), (D)-(IV)
  4. (A)-(IV), (B)-(II), (C)-(III), (D)-(I)
Ques. 6JEE Main 2025, 23 January (Morning Shift)

The correct set of ions (aqueous solution) with same colour from the following is:

  1. V2+, Cr3+, Mn3+
  2. Ti4+, V4+, Mn2+
  3. Sc3+, Ti3+, Cr2+
  4. Zn2+, V3+, Fe3+
Ques. 7JEE Main 2025, 23 January (Evening Shift)

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

  1. A-IV, B-II, C-III, D-I
  2. A-IV, B-III, C-I, D-II
  3. A-III, B-I, C-IV, D-II
  4. A-III, B-IV, C-II, D-I
Ques. 8JEE Main 2025, 23 January (Evening Shift)

Consider the following reactions K2Cr2O7 [-H2O]KOH [A] [-H2O]H2SO4 [B] + K2SO4 The products [A] and [B], respectively are :

  1. K2Cr(OH)6 and Cr2O3
  2. K2CrO4 and Cr2O3
  3. K2CrO4 and K2Cr2O7
  4. K2CrO4 and CrO
Ques. 9JEE Main 2025, 22 January (Morning Shift)

Lanthanoid ions with 4f7 configuration are : Choose the correct answer from the options given below :

  1. B and E only
  2. B and C only
  3. A and D only
  4. A and B only
Ques. 10JEE Main 2024, 9 April (Morning Shift)

The electronic configuration of Cu(II) is 3d9 whereas that of Cu(I) is 3d10. Which of the following is correct?

  1. Cu(II) is more stable
  2. Cu(II) is less stable
  3. Cu(I) and Cu(II) are equally stable
  4. Stability of Cu(I) and Cu(II) depends on nature of copper salts
Ques. 11JEE Main 2024, 9 April (Morning Shift)

Number of colourless lanthanoid ions among the following is . Eu3+, Lu3+, Nd3+, La3+, Sm3+

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