d-Block and f-Block Elements Test - 3

Which among the following elements does not belong to first transition series?

The number of unpaired electrons in Mn²⁺ (25) is

The following question has four choices, out of which ONLY ONE is correct.

Potassium permanganate is reduced to Mn²⁺ in acidic solution.
MnO₄^– + 8H⁺ + 5e^– → Mn²⁺ + 4H₂O
In neutral or weakly basic medium, however, it is reduced to Mn (IV) state.
MnO₄^– + 2H₂O + 3e^– → MnO₂ + 4OH^–
In acidic medium, Cr₂O₇^2- is reduced to Cr³⁺.
Cr₂O₇^2– + 14H⁺ + 6e^– → 2Cr³⁺ + 7H₂O

100 ml of a 0.1 M solution of a reducing agent whose equivalent weight is equal to its molecular weight in both acidic and alkaline media requires 75 ml of a KMnO₄ solution in acidic medium for complete oxidation. What is the molar concentration of the KMnO₄ solution if the titration is carried out in alkaline medium?

Transition metal compounds are usually coloured. This is due to the electronic transitions

Compounds of most lanthanoids occur in +3 oxidation state. Which of the following formulae of the compounds of lanthanoids is incorrect?

The relative composition of lanthanides in mischmetal is

Transition metals with lowest melting point is

Which of the following pairs has comparable values of atomic radii as well as ionization energies?

Which among the following transition metal has lowest melting point?

A metal halide, on reaction with potassium dichromate in the presence of conc. H₂SO₄, gives red vapours of a gas. The halide ion and the gas evolved respectively are