PYQSide ExamsMy practice

d- and f-Block Elements · Question 37

JEE Main 2025 (Online) 29th January Morning ShiftMCQHard📈 Topic in 13% papers+4−1
1

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

Answer

(4) Mn < Fe, Tc < Ru and Os < Re

Solution

(Mn, Fe): Mn (3d5 4s2) has an exceptionally low melting point due to weak metallic bonding of the stable half-filled d5 set: Mn (1519 K) < Fe (1811 K)

(Tc, Ru): Tc (2430 K) < Ru (2607 K)

(Re, Os): In the 5d series the maximum lies at Re/W: Re (3459 K) > Os (3306 K) Os < Re

Mn < Fe, Tc < Ru and Os < Re

Answer: (4)

JEE Main 2025 (Online) 29th January Morning Shift

Keep practising — d- and f-Block Elements

2

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
3

Consider 'n' is the number of lone pair of electrons present in the equatorial position of the most stable structure of ClF3. The ions from the following with 'n' number of unpaired electrons are Choose the correct answer from the options given below:

  1. B and D Only
  2. A, D and E Only
  3. B and C Only
  4. A and C Only
JEE Main 2025 (Online) 28th January Morning Shift
4

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
JEE Main 2025 (Online) 28th January Morning Shift
5

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
JEE Main 2025 (Online) 28th January Evening Shift
6

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).

JEE Main 2025 (Online) 28th January Evening Shift

All d- and f-Block Elements PYQs →

PDFDownload d- and f-Block Elements PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All JEE Main Chemistry chapters
Physical ChemistrySome Basic Concepts of ChemistryStructure of AtomStates of MatterThermodynamicsEquilibriumRedox ReactionsSolutionsElectrochemistryChemical Kinetics
Inorganic ChemistryClassification of Elements and Periodicity in PropertiesChemical Bonding and Molecular Structurep-Block Elements (Group 13 & 14)p-Block Elements (Group 15–18)d- and f-Block ElementsCoordination Compounds
Organic ChemistryOrganic Chemistry – Some Basic Principles and TechniquesIsomerismHydrocarbonsHaloalkanes and HaloarenesAlcohols, Phenols and EthersAldehydes, Ketones and Carboxylic AcidsAminesBiomoleculesPrinciples Related to Practical Chemistry