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

383.

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