The reason for greater range of oxidation states in actinoids is attributed to

• The radioactive nature of actinoids

• Actinoid contraction

• 5f, 6d and 7s levels having comparable energies

• 5f, 6d and 7s levels having comparable energies

Name the gas that can readily decolourises acidified KMnO₄ solution

• CO₂

• SO₂

• NO₂

• NO₂

The correct increasing order of ionic radii of the following Ce³⁺, La³⁺, Pm³⁺ and Yb³⁺ is 

• Yb³⁺ < Pm³⁺< Ce³⁺<La³⁺

• Ce³⁺< Yb³⁺<Pm³⁺<La³⁺

• Yb³⁺< Pm³⁺< La³⁺<Ce³⁺

• Pm³⁺ < La³⁺< Ce³⁺ < Yb³⁺

The shape of gaseous SnCl₂ is

• Tetrahedral

• Linear

• Angular

• T-shape

[CuCl₄]^2- exists while [CuI₄]^2- does not exist, because

• I^- is stronger reductant than Cl^-

• I^- is weaker reductant than Cl^-

• I^- is stronger oxidant than Cl^-

• None of the above

Actinides exhibit larger number of oxidation state than that of corresponding lanthanides. The reason behind this aspect is

• lesser energy difference between 5f and 6d-orbitals than between 4f and 5d-orbitals

• larger atomic size of actinides than the lanthanides

• more energy difference between 5f and 6d orbitals than between 4f and 5d-orbitals

• greater reactive nature of the actinides than the lanthanides

Acidified K₂Cr₂O₇ solution turns green when Na₂SO₃ is added to it. This is due to the formation of

• Cr${\mathrm{O}}_4^{2-}$

• Cr₂(SO₃)₃

• CrSO₄

• Cr₂(SO₄)₃

Which one of the following is 'd-block element?

• Gd

• Hs

• Es

• Cs

Point out the incorrect reaction from the following.

• 2Na₂CrO₄ + H⁺ $\to$ Na₂Cr₂O₇ + 2Na⁺ + H₂O

• 4MnO₂ + 4KOH + O₂ $\to$ 4KMnO₄ + 2H₂O

• 2Mn${\mathrm{O}}_4^{-}$ + 5C₂${\mathrm{O}}_4^{2-}$ + 16H⁺ $\to$ 2Mn²⁺ + 10CO₂ + 8H₂O

• Mn${\mathrm{O}}_4^{-}$ + 8H⁺ + 5Fe²⁺ $\to$5Fe³⁺ + Mn²⁺ + 4H₂O

On addition of small amount of KMnO₄ to conc. H₂SO₄, a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following

• Mn₂O₇

• MnO₂

• MnSO₄

• Mn₂O₃