ExamGOAL
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54
Subjective

Match the properties given in Column I with the metals given in Column II.

Column I
(Property)
Column II
(Metal)
A. An element which can show +8 oxidation state 1. Mn
B. 3d block element that can show upto +7 oxidation state 2. Cr
C. 3d block element with highest melting point 3. Os
4. Fe

Explanation

A. $\rightarrow(3)$ B. $\rightarrow$ (1) C. $\rightarrow(2)$

A. Osmium is an element which can show +8 oxidation state.

B. $3 d$ block element that can show upto +7 oxidation state is manganese.

C. $3 d$ block element with highest melting point is chromium.

55
Subjective

Match the statements given in Column I with the oxidation states given in Column II.

Column I
Column II
A. Oxidation state of Mn in MnO$_2$ is 1. +2
B. Most stable oxidation state of Mn is 2. +3
C. Most stable oxidation state of Mn in oxides is 3. +4
D. Characteristic oxidation state of lanthanoid is 4. +5
5. +7

Explanation

A. $\rightarrow(3)$ B. $\rightarrow$ (1) C. $\rightarrow$ (5) D. $\rightarrow(2)$

A. Oxidation state of Mn in $\mathrm{MnO}_2$ is +4 .

B. Most stable oxidation state of Mn is +2 .

C. Most stable oxidation state of Mn in oxides is +7 .

D. Characteristic oxidation state of lanthanoids is +3 .

56
Subjective

Match the solutions given in Column I and the colours given in Column II.

Column I
(Aqueous solution of salt)
Column II
(Colour)
A. $\mathrm{FeSO_4 . 7H_2O}$ 1. Green
B. $\mathrm{NiCl_2 . 4H_2O}$ 2. Light pink
C. $\mathrm{MnCl_2 4H_2O}$ 3. Blue
D. $\mathrm{CoCl_2 . 6H_2O}$ 4. Pale green
E. $\mathrm{Cu_2Cl_2}$ 5. Pink
6. Colourless

Explanation

A. $\rightarrow$ (4) B. $\rightarrow$ (1) C. $\rightarrow(2)$ D. $\rightarrow$ (5) E. $\rightarrow$ (6)

(Aqueous solution of salt) (Colour)
A. $\mathrm{FeSO_4 . 7H_2O}$ 1. Pale green
B. $\mathrm{NiCl_2 . 4H_2O}$ 2. Green
C. $\mathrm{MnCl_2 4H_2O}$ 3. Light pink
D. $\mathrm{CoCl_2 . 6H_2O}$ 4. Pink
E. $\mathrm{Cu_2Cl_2}$ 5. Colourless

57
Subjective

Match the property given in Column I with the element given in Column II.

Column I
(Property)
Column II
(Element)
A. Lanthanoid which shows +4 oxidation state 1. Pm
B. Lanthanoid which can show +2 oxidation state 2. Ce
C. Radioactive lanthanoid 3. Lu
D. Lanthanoid which has $4f^7$ electronic configuration in +3 oxidation state 4. Eu
E. Lanthanoid which has $4f^{14}$ electronic configuration in +3 oxidation state 5. Gd
6. Dy

Explanation

A. $\rightarrow(2)$ B. $\rightarrow$ (4) C. $\rightarrow$ (1) D. $\rightarrow(5)$ E. $\rightarrow$ (3)

A. Lanthanoid which shows +4 oxidation state is cerium.

${ }_{58} \mathrm{Ce}=[\mathrm{Xe}] 4 f^2 5 d^0 6 \mathrm{~s}^2 ;$ Oxidation state $=+3,+4$

B. Lanthanoid which can show +2 oxidation state is europium.

${ }_{63} \mathrm{Eu}=[\mathrm{Xe}] 4 f^7 5 d^0 6 \mathrm{~s}^2$; Oxidation state $=+2,+3$

C. Radioactive lanthanoid is promethium. It is the only synthetic (man-made) radioactive lanthanoid.

D. Lanthnoid which has $4 f^7$ electronic configuration in +3 oxidation state is gadolinium.

${ }_{64} \mathrm{Gd}=[\mathrm{Xe}] 4 f^7 5 d^1 6 s^2$; Oxidation state $=+3$

E. Lanthanoid which has $4 f^{14}$ electronic configuration in +3 oxidation state is lutetium

${ }_{71} \mathrm{Lu}=[\mathrm{Xe}] 4 f^{14} 5 d^1 6 s^2 ;$ Oxidation state $=+3$

58
Subjective

Match the properties given in Column I with the metals given in Column II.

Column I
(Property)
Column II
(Metal)
A. Element with highest second ionisation enthalpy 1. Co
B. Element with highest third ionisation enthalpy 2. Cr
C. M in M(CO)$_6$ is 3. Cu
D. Element with highest heat of atomisation 4. Zn
5. Ni

Explanation

A. $\rightarrow(3)$ B. $\rightarrow$ (4) C. $\rightarrow(2)$ D. $\rightarrow$ (1)

A. $\mathrm{Cu}^{+}=3 d^{10}$ which is very stable configuration due to full-filled orbitals. Hence, removal of second electron requires very high energy.

B. $\mathrm{Zn}^{2+}=3 d^{10}$ which is very stable configuration. Hence, removal of third electron requires very high energy.

C. Metal carbonyl with formula $\mathrm{M}(\mathrm{CO})_6$ is $\mathrm{Cr}(\mathrm{CO})_6$.

D. Nickel is the element with highest heat of atomisation.