Yellow colour of aqueous solution of potassium chromate changes to orange if dil. H₂SO₄ is added. It indicates:

• chromate ions are reduced

• chromate ions are oxidised

• monocentric complex is converted into dicentric complex

• oxygen gets removed from chromate ions

Which of the following dissolves in hot conc. NaOH solution?

• Fe

• Zn

• Cu

• Ag

Which one of the following represents d-block elements?

• [Rn]6d² , 7s²

• [Xe]4f¹ , 5d¹ , 6s²

• [Xe]4f¹⁴ , 5d¹ , 6s²

• [Xe]5d¹ , 6s²

Pd has exceptional outer electronic configuration as 4d¹⁰ , 5s⁰. It belongs to:

• 4th period , group 11

• 5th period , group 10

• 6th period , group 9

• 3th period , group 16

For the same transition metal ion, the colour of its compounds will depend upon:

• temperature of the reaction

• pressure of the reaction

• nature of ligands or Lewis bases attached to the metal ion

• concentration of the ligands

The 3^rd transitional series contain elements having atomic numbers from:

• 21 to 29

• 21 to 30

• 20 to 30

• 21 to 31

The transition metals mostly are

• paramagnetic

• diamagnetic

• both 'a' and 'b'

• neither diamagnetic nor paramagnetic

Among the oxides, Mn₂O₇ (I) , V₂O₃ (II) , V₂O₅ (III) , CrO (IV) , Cr₂O₃ (V) the basic oxides are :

• I and II

• II and III

• III and IV

• II and IV

249.

The oxygen carrying pigment , oxyhaemocyanin containing two copper ions is diamagnetic , because :

• the two copper ions are in + 1oxidation state

• one copper ion is in + 1oxidation state while other is in + 2 oxidation state

• of the strong antiferromagnetic interactions between two copper ions

• of the ferromagnetic interactions between the two copper ions

Which is not true statement ?

• Ions of d-block elements are coloured due to d-d transition

• Ions of f-block elements are coloured due to f-f transition

• [Sc(H₂O)₆]³⁺ , [Ti(H₂O)₆]⁴⁺ are coloured complexes

• Cu⁺ is colourless ion