The d-And-f-Block Elements

Transition metal ions show colour because

• they absorb light

• They emit light

• They are paramagentic

• they exhibit d-d transition

Transitional metal ions have an ability of complex formation. They have this tendency due to

• catalytic property

• high enthalpy of atomisation

• high nuclear charge

• All of the above

In the reduction of KMnO₄ by warm acidified oxalic acid, the oxidation number of Mn changes from

• +4 to +2

• +6 to +4

• +7 to +2

• +7 to +4

Transition metals have the electronic configuration (n -1)d^1-10ns^1-2. The d-orbitals are degenerate. Colour of transition metal ions is due to absorption of some wavelength. This result is

• d-s transition

• s-d transition

• s-s transition

• d-d transition

Manganese salt + PbO₂ + conc. HNO₃ → the solution acquires purple colour. The colour is due to

• Mn(NO₃)₂

• Pb(NO₃)₂

• HMnO₄

• MnO

Acidified solution of chromic acid on treatment with H₂O₂ yields

• CrO₃ + H₂O + O₂

• Cr₂O₃ + H₂O + O₂

• CrO₅ + H₂O

• H₂Cr₂O₇ + H₂O + O₂

German silver contains which following metals?

• Cu, Zn

• Fe, Zn

• Zn, Fe, Ni

• Cu, Zn, Ni

Which one of the following lanthanide ions does not exhibit paramagnetism?

• Lu³⁺

• Ce³⁺

• Eu³⁺

• Yb³⁺

What is the change in the oxidation state of Mn in the reaction of MnO${}_4^{-}$ with H₂O₄ in acidic medium?

• 7 ➔4

• 6➔4

• 7➔2

• 6➔2

The following reaction occurs in acidic medium KMnO₄ + 8H⁺ + 5e^- → K⁺ + Mn²⁺ + 4H₂O. What is the equivalent weight of KMnO₄ ?

(Molecular weight of KMnO₄ = 158)

• 79.0

• 31.6

• 158.0

• 39.5