The d-And-f-Block Elements

Which of the following statements regarding Lanthanides is false?

• All lanthanides are solid at room temperature

• Their usual oxidation state is +3

• They can be separated from one another by ion-exchange method

• Ionic radii of trivalent lanthanides steadily increases with increase in atomic number

The correct basicity order of the following lanthanide ions is

• La³⁺ > Lu³ > Ce³⁺ > Eu³⁺

• Ce³⁺ > Lu³⁺ > La³⁺ > Eu³⁺

• Lu³⁺ > Ce³⁺ > Eu³⁺ > La³⁺

• La³⁺ > Ce³⁺ > Eu³⁺ > Lu³⁺

Extraction of gold (Au) involves the formation of complex ions X and Y.

Gold ore $\underset{{\mathrm{CN}}^{-}, {\mathrm{H}}_2\mathrm{O}, {\mathrm{O}}_2}{\overset{\mathrm{Roasting}}{\to }}$ HO^- + X $\stackrel{\mathrm{Zn}}{\to }$ Y + Au

X and Y respectively are

• Au(CN)${}_2^{-}$ and Zn(CN)${}_4^{2-}$

• Au(CN)${}_4^{3-}$ and Zn(CN)${}_4^{2-}$

• Au(CN)${}_3^{-}$ and Zn(CN)${}_6^{2-}$

• Au(CN)${}_4^{-}$ and Zn(CN)${}_3^{-}$

The atomic number of cerium (Ce) is 58. The correct electronic configuration of Ce³⁺ ion is

• [Xe]4f¹

• [Kr]4f¹

• [Xe]4f¹³

• [Kr]4d¹

Cold ferrous sulphate solution on absorption of NO develops brown colour due to the formation of

• paramagnetic [Fe(H₂O)₅(NO)]SO₄

• dimagnetic [Fe(H₂O)₅(NO)]SO₄

• paramagnetic [Fe(H₂O)₅(NO₃)][SO₄]₂

• diamagnetic [Fe(H₂O)₄(SO₄)]NO₃

Roasted copper pyrite on smelting with sand produces

• FeSiO₃ as fusible slag and Cu₂S as matte

• CaSiO₃ as infusible slag and Cu₂O as matte

• Ca₃(PO₄)₂ as fusible slag and Cu₂S as matte

• Fe₃(PO₄)₂ as infusible slag and Cu₂S as matte

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 Cu⁺ is less than Cu²⁺

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

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

The ore chromite is

• FeCr₂O₄

• CoCr₂O₃

• CrFe₂O₄

• FeCr₂O₃

Li occupies higher position in the electrochemical series of metals as compared to Cu since

• the standard reduction potential of Li⁺/Li is lower than that of Cu²⁺ /Cu

• the standard reduction potential of Cu²⁺/Cu is lower than that of Li⁺/Li

• the standard oxidation potential of Li/Li⁺ is lower than that of Cu/Cu²⁺

• Li is smaller in size as compared to Cu

The equivalent weight of K₂Cr₂O₇ in acidic medium is expressed in terms of its molecular weight (M) as

• M/3

• M/4

• M/6

• M/7