31.

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

The crystal field splitting for Cr³⁺ ion in an octahedral field increases for ligands I^- , H₂O , NH₃ , CN^- and the order is :

• I^- < H₂O < NH₃ < CN^-

• CN^- < I^- < H₂O < NH₃

• CN^- < NH₃ < H₂O < I^-

• NH₃ < H₂O < I^- < CN^-

The reaction between metallic silver and aqueous NaCN forming a soluble complex occurs in the presence of :

• nitrogen

• oxygen

• helium

• chlorine

A mineral having the formula AB₂ crystallizes in the cubic close-packed lattice , with the A atoms occupying the lattice points. The fraction of the tetrahedral sites occupied by B atoms is :

• 20 %

• 40 %

• 60 %

• 100 %

Which one of the following is incorrect ?

• Ionisation enthalpy of molecular oxygen is very close to that of Xe

• Only type of interatomic interaction between particles of noble gases are weak dispersion forces

• Hydrolysis of XeF₆ is not a redox reaction

• Xenon fluorides are not reactive

Which one ofthe following nitrogen oxides does not contain N-N bonds?

• N₂O

• N₂O₃

• N₂O₄

• N₂O₅

Extent of adsorption of adsorbate from solution phase increases with :

• increase in amount of adsorbate in solution

• decrease in surface area of adsorbent

• increase irtemperature of solution

• decrease in amount of adsorbate in solution

Which ofthe following is a negatively charged sol ?

• Sol of charcoal

• Haemoglobin

• TiO₂ sol

• Basic dye stuffs

Which of the following elements is present as the impurity to the maximum extent in pig iron ?

• Phosphorus

• Manganese

• Carbon

• Silicon

Which metallurgy does not involve leaching ?

• Fe

• Ag

• Au

• Al