691.

Which of the following does not give oxygen on heating?

• KClO₃

• Zn(ClO₃)₂

• K₂Cr₂O₇

• (NH₄)₂Cr₂O₇

Which ofthe following lanthanoid ions is diamagnetic?
(At. nos. Ce = 58, Sm = 62, Eu = 63, Yb= 70)

• Ce²⁺

• Sm²⁺

• Eu²⁺

• Yb²⁺

Platinum, palladium and iridium are called noble metals because:

• Alfred Nobel discovered them

• they are shining lustrous and pleasing to look at

• they are found in native state

• they are inert towards many common reagents

Cupric compounds are more stable than their cuprous counterparts in solid state. This is because

• the endothermic character of the 2nd IP of Cu is not so high

• size of Cu²⁺ is less than Cu⁺

• Cu²⁺ has stable electronic configuration as compared to Cu⁺

• the lattice energy released for cupric compounds is much higher than Cu⁺

Explain briefly the cause of Lanthanoid contraction.

Anhydrous ferric chloride is prepared by:

• dissoving Fe(OH)₃ in concentrated HCl

• dissolving Fe(OH)₃ in dilute HCl

• passing dry HCl overheated iron scrap

• passing dry Cl₂ gas overheated iron scrap

For which element the inertness of the electron pair will not be observed? 

• Sn

• Fe

• Pb

• In

Composition of azurite mineral is

• CuCO₃.CuO

• Cu(HCO₃)₂.Cu(OH)₂

• 2CuCO₃.Cu(OH)₂

• CuCO₃.2Cu(OH)₂

When H₂S gas is passed in a metal sulphate solution in presence of NH₄OH, a white precipitate is produced. The metal is identified as:

• Zn

• Fe

• Pb

• Hg

Which of the following is philosopher's wool ?

• ZnO

• HgO

• Ag₂O

• CuO