Which of the following element does not show variable valency ?

• Ni

• Zn

• Cu

• Mn

For decolourization of 1 mole of KMnO₄, the moles of H₂O₂ required is

• 1/2

• 3/2

• 5/2

• 7/2

Lanthanide for which +II and +III oxidation states are common is

• La

• Nd

• Ce

• Eu

The compound used for gravimetric estimation of copper(II) is

• Cu₂(SCN)₂

• Cu₂O

• Cu₂I₂

• Cu₂CO₃

Which of the following has highest second  ionization energy?

• Ni

• V

• Cr

• Mn

Which of the following compound is not coloured?

• Na₂[CuCl₄]

• Na₂[CdCl₄]

• K₄[Fe(CN)₆]

• K₃[Fe(CN)₆]

687.

The electronic configuration of Cu is

• [Ne] 3s², 3p⁶, 3d⁹, 4s²

• [Ne] 3s², 3p⁶, 3d¹⁰, 4s¹

• [Ne] 3s², 3p⁶, 3d³, 3d⁹, 4s², 4p⁶

• [Ne] 3s², 3p⁶, 3d⁵, 4s², 4p⁴

Assertion: Cuprous ion (Cu⁺) is colorless whereas cupric ion (Cu²⁺) is blue in the aqueous solution.
Reason: Cuprous ion (Cu⁺) has unpaired electrons while cupric ion (Cu²⁺) does not.

• If both assertion and reason are true and reason is a correct explanation of the assertion.

• If both the assertion and reason are true but the reason is not a correct explanation of the assertion.

• If the assertion is true but the reason is false.

• If both the assertion and reason are false.

The stable bivalency of Pb and trivalencey of Bi is:

• due to d contraction in Pb and Bi

• due to relativistic contraction of the 6s orbitals of Pb and Bi, leading to inert pair effect

• due to screening effect

• due to the attainment of noble liquid configuration

A magnetic moment of 1.73 BM will be shown by one among the following

• [Cu(NH₃)₄]²⁺

• [Ni(CN)₄]^2-

• TiCl₄

• [CoCl₆]^4-