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d- and f-Block Elements · Question 40

JEE Main 2025 (Online) 28th January Morning ShiftMCQMedium📈 Topic in 16% papers+4−1
1

Which of the following oxidation reactions are carried out by both K2Cr2O7 and KMnO4 in acidic medium? Choose the correct answer from the options given below :

  1. A, B and C Only
  2. C, D and E Only
  3. B, C and D Only
  4. A, D and E Only

Answer

(1) A, B and C Only

Solution

Acidic K2Cr2O7 (NCERT):

Cr2O72- + 14H+ + 6I- 2Cr3+ + 3I2 + 7H2O

Cr2O72- + 8H+ + 3H2S 2Cr3+ + 3S + 7H2O

Cr2O72- + 14H+ + 6Fe2+ 2Cr3+ + 6Fe3+ + 7H2O

Acidic KMnO4 (NCERT):

2MnO4- + 16H+ + 10I- 2Mn2+ + 5I2 + 8H2O

2MnO4- + 16H+ + 5S2- 2Mn2+ + 5S + 8H2O

MnO4- + 8H+ + 5Fe2+ Mn2+ + 5Fe3+ + 4H2O

I- IO3- and S2O32- SO42- are brought about by KMnO4 in neutral or faintly alkaline medium, not by both oxidants in acidic medium.

A, B and C.

Answer: (1)

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Keep practising — d- and f-Block Elements

2

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
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3

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).

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