Revisial Problems (Past 13 Year) JEE Main (D Block Elements) - JEE MCQ

A metal is soluble in acid if it displaces H₂ from solution, which is determined by the metal’s standard reduction potential. Cu, Ag, Pt and Au cannot displace H₂.

Only Cu shows +1 oxidation state.

In MnO₂, manganese is in Mn⁴⁺ form. Hence, the configuration is [Ar] 3d³.

Rutile is a mineral compared primarily of titanium dioxide, TiO₂.

The order of increasing atomic radii is Ni < Mn < Ti < La

Colour of the compounds of the same transition metal ion depends upon the nature of ligand attached to it, e.g. [CuCl₄]^2- is greenish yellow, [Cu(H₂O)₄]²⁺ is blue but[Cu(NH₃)₄]²⁺ is violet or deep blue.

Both have 23 electrons each.

Metal oxide with higher oxidation number exhibit acidic nature.

Smaller the ion, more is the hydration and also hydration energy.

Cobalt +2 ion is blue pink in colour.

Addition of high proportions of Mn gives hardness to steel which is used for making rails of rail roads.

Both Hg²⁺ and do not have unpaired electron.

In (i), (ii) and (iii), same element is undergoing both oxidation and reduction.

Mn₂O₇ = acidic , CrO₃ = acidic , Cr₂O₃ = amphoteric,
CrO = basic, V₂O₅ = acidic, V₂O₄ = amphoteric oxides.

Interstitial compounds are chemically inert.

Consider one mole of the oxide, moles of M = 0.98 and moles of O2^- = 1
Let moles of M³⁺ = x and moles of M²⁺ = 0.98 - x
During charge balance (0.98 - x) x 2 + 3 x - 2 = 0
On solving, we get x = 0.04,

All others have sp³ hybridisation with tetrahedral shape. [Ni(CN)₄]^2- have dsp²-hybridisation.

Mn³⁺ + e^- → Mn²⁺ , E° = + 1.57 V
Co³⁺ + e^- → Co²⁺ , E° = + 1.97 V

(i) One equivalent dichromate = one equivalent ferrous oxalate or 1/6 mole dichromate = 1/3 mole ferrous oxalate Three moles dichromate = six moles ferrous oxalate = 0.5 mole dichromate
(ii) In ferric oxalate, only oxalate ion undergo oxidation 1/6 mole, dichromate = 1/2 mole ferric oxalate Two mole dichromate = six mole ferrous oxalate or one mole ferrous oxalate = 0.33 mole dichromate

In neutral or weakly basic medium, perm anganate ion is reduced to MnO₂.

Eu =[Xe] 4f⁷5d⁰ 6s²;Eu shows +2 and + 3 oxidation states.

2MnO₂ + 4KOH + O₂ → 2K₂MnO₄ + 2H₂O

Promethium is synthetic and radioactive element.

Ti³⁺ have onecf-electron which is responsible for its colour. d-d transition occurs here.

Oxidising agent gains electron and reducing agent loses electrons.
Ce(IV) gain electron to become Ce (III) and hence, strong oxidising agent.
Eu (II) loses one electron to become Eu (III) and hence, act as reducing agent.

Eu = [Xe] 4f⁷5d⁰ 6s² and Yb = [Xe] 4f¹⁴5d⁰ 6s². Removal of 3rd electron requires more energy from these elements.