D Block Elements Properties Uses

Which one of the following ions is the most stable in an aqueous solution?
(At. No. Ti = 22, V = 23, Cr = 24, Mn = 25)

1.

2.

3.

4.

The d-electron configurations of Cr²⁺, Mn²⁺, Fe²⁺ and Ni²⁺ and 3d⁴, 3d⁵, 3d⁶ and 3d⁸ respectively.
Which one of the following aqua complexes will exhibit the minimum paramagnetic behaviour?
(At. No. Cr = 24, Mn = 25, Fe = 26, Ni = 28)

1.
2.
3.
4.

Which one of the elements with the following outer orbital configurations may exhibit the largest number of oxidation states?

1. 3d³, 4s²

2. 3d⁵, 4s¹

3. 3d⁵, 4s²

4. 3d², 4s²

Which one of the following ions has electronic configuration [Ar] 3d⁶?
(At. no :Mn = 25, Fe= 26, Co= 27, Ni = 28)

1. $N{i}^{3+}$

2. $M{n}^{3+}$

3. $F{e}^{3+}$

4. $C{o}^{3+}$

Which of the following pairs has the same size?

1. $F{e}^{2+},$ $N{i}^{2+}$

2. $Z{r}^{4+},$ $T{i}^{4+}$

3. $Z{r}^{4+},$ $H{f}^{4+}$

4. $Z{n}^{2+},$ $H{f}^{4+}$

1. Fe>Mn>Co>Cr

2. Co>Mn>Fe>Cr

3. Cr>Mn>Co>Fe

4. Mn>Fe>Cr>Co

Acidified K₂Cr₂O₇ solution turns green when Na₂SO₃ is added to it. This is due to the formation of:

1. ${\mathrm{CrO}}_4^{2-}$

2. ${\mathrm{Cr}}_2{\left({\mathrm{SO}}_3\right)}_3$

3. ${\mathrm{CrSO}}_4$

4. ${\mathrm{Cr}}_2{\left({\mathrm{SO}}_4\right)}_3$

Which of the following statements is false?

1.	On passing H2S through acidified K2Cr2O7 solution, a milky colour is observed.
2.	Na2Cr2O7 is preferred over K2Cr2O7 in volumetric analysis.
3.	K2Cr2O7 solution in an acidic medium is orange.
4.	K2Cr2O7 solution becomes yellow in increasing the pH beyond 7

The incorrect statement among the following regarding interstitial compounds is:
1. They are chemically reactive.
2. They are much harder than the pure metal.
3. They have a higher melting point than pure metals.
4. They retain metallic conductivity.

Assuming complete ionization, same moles of which of the following compounds will require the least amount of acidified KMnO₄ for complex oxidation?

1. $FeS{O}_4$

2. $FeS{O}_3$

3. $Fe{C}_2{O}_4$

4. $Fe{\left(N{O}_2\right)}_2$

Zinc can be coated on iron to produce galvanised iron, but the reverse is not possible because:

1.	Zinc is lighter than iron.
2.	Zinc has a lower melting point than iron.
3.	Zinc has a lower negative reduction potential than iron.
4.	Zinc has a higher negative reduction potential than iron.

A gas that can readily decolorize an acidified KMnO₄ solution is:

1.	SO2	2.	NO2
3.	P2O5	4.	CO2

HgCl₂ and I₂ both, when dissolved in water containing ${\mathrm{I}}^{-}$ ions the pair of species formed is:

1. ${\mathrm{HgI}}_2,$ ${\mathrm{I}}^{-}$

2. ${\mathrm{HgI}}_4^{2-},$ ${\mathrm{I}}_3^{-}$

3. ${\mathrm{Hg}}_2{\mathrm{I}}_2,$ ${\mathrm{I}}^{-}$

4. ${\mathrm{HgI}}_2,$ ${\mathrm{I}}_3^{-}$

The reason for a greater range of oxidation states in actinoids is attributed to:

1. Actinoid contraction

2. 5f, 6d and 7s levels having comparable energies.

3. 4f and 5d levels being close in energies.

4. The radioactive nature of actinoids

Match Column-I with Column-II and mark the most appropriate option:

	Column-I (Metal ion)		Column-II (Spin magnetic moment)
A.	Co3+	i.	√8 B.M.
B.	Cr3+	ii.	√35 B.M.
C.	Fe3+	iii.	√15 B.M.
D.	Ni2+	iv.	√24 B.M.

	A	B	C	D
1.	iv	iii	ii	i
2.	i	ii	iii	iv
3.	iv	i	ii	iii
4.	iii	iv	i	ii

Match the following aspects with the respective metal:

	Aspects		Metal
(a)	The metal that reveals the maximum number of oxidation states	(i)	Scandium
(b)	The metal, although placed in a 3d block, is not considered a transition element	(ii)	Copper
(c)	The metal that does not exhibit variable oxidation states	(iii)	Manganese
(d)	The metal, which is in +1 oxidation state in aqueous solution, undergoes disproportionation	(iv)	Zinc

Select the correct option:

Options:	(a)	(b)	(c)	(d)
1.	(i)	(iv)	(ii)	(iii)
2.	(iii)	(iv)	(i)	(ii)
3.	(iii)	(i)	(iv)	(ii)
4.	(ii)	(iv)	(i)	(iii)

Identify the incorrect statement from the following:

1.	The shapes of dxy, dyz, and dzx orbitals are similar to each other; and dx2 -y2 and dz2 are similar to each other.
2.	All the five 5d orbitals are different in size when compared to the respective 4d orbitals.
3.	All the five 4d orbitals have shapes similar to the respective 3d orbitals.
4.	In an atom, all the five 3d orbitals are equal in energy in free state.

In the neutral or faintly alkaline medium, oxidises iodide into iodate. The change in oxidation state of manganese in this reaction is from:

1.	+6 to +5	2.	+7 to +4
3.	+6 to +4	4.	+7 to +3

The stability of Cu²⁺ is greater than that of Cu⁺ salts in an aqueous solution due to:

1. Second ionisation enthalpy
2. First ionisation enthalpy
3. Enthalpy of atomization
4. Hydration energy

Which of the following statements is incorrect?

A.	All the transition metals except scandium form MO oxides which are ionic.
B.	The highest oxidation number corresponds to the group number in transition metal oxides is attained in Sc2O3 to Mn2O7.
C.	Basic character increases from V2O3 to V2O4 to V2O5.
D.	V2O4 dissolves in acids to give VO43-.
E.	CrO is basic, but Cr2O3 is amphoteric.

Choose the correct answer from the options given below:

1.	B and C only	2.	A and E only
3.	B and D only	4.	C and D only

The E° value for the Mn³⁺/Mn²⁺ couple is more positive than that of Cr³⁺/Cr²⁺ or Fe³⁺/Fe²⁺ due to change of:

1.	d5 to d2 configuration	2.	d4 to d5 configuration
3.	d3 to d5 configuration	4.	d5 to d4 configuration

Which of the following ions have the same 'spin-only' magnetic moment?

A.	Ti+3	B.	Cr2+
C.	Mn2+	D.	Fe2+
E.	Sc3+

Choose the most appropriate answer from the options given below:

1.	A and E only	2.	B and C only
3.	A and D only	4.	B and D only