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d- and f-Block Elements · Question 28

JEE Main 2025 (Online) 7th April Evening ShiftMCQMedium📈 Topic in 13% papers+4−1
1

'X' is the number of acidic oxides among VO2, V2O3, CrO3, V2O5 and Mn2O7. The primary valency of cobalt in [Co(H2NCH2CH2NH2)3]2(SO4)3 is Y. The value of X + Y is .

  1. 3
  2. 4
  3. 2
  4. 5

Answer

(4) 5

Solution

As per NCERT, the acidic character of transition metal oxides increases with the oxidation state of the metal:

V2O3 (+3): basic; VO2 (+4): amphoteric; V2O5 (+5): amphoteric (mainly acidic)

CrO3 (+6): acidic; Mn2O7 (+7): acidic

X = 2

In [Co(en)3]2(SO4)3: 2x + 3(-2) = 0 x = +3

Y = primary valency = 3

X + Y = 2 + 3 = 5

Answer: (4)

JEE Main 2025 (Online) 7th April Evening Shift

Keep practising — d- and f-Block Elements

2

Pair of transition metal ions having the same number of unpaired electrons is

  1. Ti3+, Mn2+
  2. Ti2+, Co2+
  3. Fe3+, Cr2+
  4. V2+, Co2+
JEE Main 2025 (Online) 4th April Morning Shift
3

KMnO4 acts as an oxidising agent in acidic medium. 'X' is the difference between the oxidation states of Mn in reactant and product. 'Y' is the number of 'd' electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of X + Y is .

JEE Main 2025 (Online) 4th April Morning Shift
4

The incorrect relationship in the following pairs in relation to ionisation enthalpies is :

  1. Mn2+ < Fe2+
  2. Mn+ < Mn2+
  3. Mn+ < Cr+
  4. Fe2+ < Fe3+
JEE Main 2025 (Online) 4th April Evening Shift
5

The metal ions that have the calculated spin-only magnetic moment value of 4.9 B.M. are : Choose the correct answer from the options given below:

  1. A, D and E Only
  2. A, B and E Only
  3. A, C and E Only
  4. B and E Only
JEE Main 2025 (Online) 3rd April Morning Shift
6

Consider the following reactions A + Little amountNaCl + H2SO4 CrO2Cl2 + Side Products CrO2Cl2(Vapour) + NaOH B + NaCl + H2O B + H+ C + H2O The number of terminal 'O' present in the compound 'C' is

JEE Main 2025 (Online) 3rd April Morning Shift
7

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

  1. Statement I is true but Statement II is false
  2. Both Statement I and Statement II are true
  3. Both Statement I and Statement II are false
  4. Statement I is false but Statement II is true
JEE Main 2025 (Online) 3rd April Evening Shift
8

Among Sc, Mn, Co and Cu, identify the element with highest enthalpy of atomisation. The spin only magnetic moment value of that element in its +2 oxidation state is BM (in nearest integer).

JEE Main 2025 (Online) 3rd April Evening Shift
9

The spin-only magnetic moment value of Mn+ ion formed among Ni, Zn, Mn and Cu that has the least enthalpy of atomisation is . (in nearest integer) Here n is equal to the number of diamagnetic complexes among K2[NiCl4], [Zn(H2O)6]Cl2, K3[Mn(CN)6] and [Cu(PPh3)3I]

JEE Main 2025 (Online) 2nd April Evening Shift
10

The correct option with order of melting points of the pairs (Mn, Fe), (Tc, Ru) and (Re, Os) is :

  1. Fe < Mn, Ru < Tc and Re < Os
  2. Fe < Mn, Ru < Tc and Os < Re
  3. Mn < Fe, Tc < Ru and Re < Os
  4. Mn < Fe, Tc < Ru and Os < Re
JEE Main 2025 (Online) 29th January Morning Shift
11

The molar mass of the water insoluble product formed from the fusion of chromite ore (FeCr2O4) with Na2CO3 in presence of O2 is g mol-1.

JEE Main 2025 (Online) 29th January Morning Shift

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