Class XII Chemistry d and f Block Elements Quiz 4

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Question 1

The number of moles of Br₂ produced when two moles of potassium permanganate are treated with excess potassium bromide in aqueous acid medium is

• A1
• B3
• C2
• D4

Question 2

The colour and magnetic nature of manganate ion is

• Agreen, paramagnetic
• Bpurple, diamagnetic
• Cgreen, diamagnetic
• Dpurple, paramagnetic

Question 3

When a brown compound of Mn (A) is treated with HCl, it gives a gas (B). The gas (B) taken in excess reacts with NH₃ to give an explosive compound (C).
The compounds A, B and C are;

• AA=MnO₂, B=Cl₂, C=NCl₃
• BA=MnO, B=Cl_2, C=NH₄Cl
• CA=Mn₃O_4, B=Cl₂, C=NCl₃
• DA=MnO₃, B=Cl₂, C=NCl_{2
  ­}

Question 4

The gas produced from thermal decomposition of (NH₄)₂Cr₂O₇ is

• Aoxygen
• Bnitric oxide
• Cammonia
• Dnitrogen

Question 5

Ni²⁺ ion (Z = 28) contains unpaired electrons

• A1
• B2
• C3
• D5

Question 6

Four successive members of the first row transition elements are listed below with atomic numbers. Which one of them is expected to have the highest value?

• AMn(Z = 25)
• BFe(Z = 26)
• CCo(Z = 27)
• DCr(Z = 24)

Question 7

Knowing that the Chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following statements is incorrect?

• ABecause of the large size of the Ln (III) ions the bonding in its compounds is predominantly ionic in character
• BThe ionic sizes of Ln (III) decrease in general with increasing atomic number
• CLn (III) compounds are generally colourless
• DLn (III) hydroxides are mainly basic in character.

Question 8

The radius of Li³⁺ (Atomic number of La = 57) is 1.06 Å. Which one of the following given values will be closest to the radius of Lu³⁺ (Atomic number of Lu = 71)?

• A1.60Å
• B1.40Å
• C1.06Å
• D0.85Å

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