A metal, M forms chlorides in it's +2 and +4 oxidation states. Which of the following statements about these chlorides is correct?

• MCl₂ is more volatile than MCl₄

• MCl₂ is more soluble in anhydrous ethanol than MCl₄

• MCl₂ is more ionic than MCl₄

• MCl₂ is more ionic than MCl₄

Lanthanoid contraction is caused due to

• the appreciable shielding on outer electrons by 4f electrons from the nuclear charge

• the appreciable shielding on outer electrons by 5d electrons from the nuclear charge

• the same effective nuclear charge from Ce to Lu

• the same effective nuclear charge from Ce to Lu

The oxidation state of chromium in the final product formed by the reaction between KI and acidified potassium dichromate solution is

• +4

• +6

• +2

• +2

The lanthanide contraction is responsible for the fact that

• Zr and Y have about the same radius

• Zr and Nb have similar oxidation state

• Zr and Hf have about the same radius

• Zr and Hf have about the same radius

Which of the following factors may be regarded as the main cause of lanthanide contraction?

• Poor shielding of one of 4f electron by another in the subshell

• Effective shielding of one of 4f electrons by another in the subshell

• Poorer shielding of 5d electrons by 4f electrons

• Poorer shielding of 5d electrons by 4f electrons

Cerium (Z = 58) is an important member of the lanthanoids. Which of the following statements about cerium is incorrect?

• The common oxidation states of cerium are +3 and +4

• Cerium (IV) acts as an oxidizing agent

• The +4 oxidation state of cerium is not known in solutions

• The +4 oxidation state of cerium is not known in solutions

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