Question

D
11. Which one of the following complexes is
diamagnetic in nature?
(1) [Cr(NH3)]3+
(2) [FeF6]3-
6
(3) [CO(NH3)6]3+
(4) [Fe(H20)6]2+
plz give proper explanation​

Answer 1

Answer:

4,because it has pair electrons in the last shell

Answer 2

Explanation:

Correct question :-

Which one of the following complexes is diamagnetic in nature?

(1) [Cr(NH3)6]³+

(2) [FeF6]³-

(3) [CO(NH3)6]³+ ✔

(4) [Fe(H20)6]³+

Solution :-

1)

$\mathsf{[Cr(NH_{3})_{6}] {}^{3 + } }$

Calculation of O.N. :-

→ x + 0×6 = 3

→ x = 3

Electronic configuration of Cr

• $\mathsf{[Ar] 4s {}^{1} 3d {}^{5} }$

Then,

$\mathsf{Electronic \: configuration \: of \: Cr {}^{3 + } }$

• $\mathsf{[Ar] 3d {}^{3} }$

Orbital diagram :-

( Refer to the attachment. )

Hence,

Magnetic character :- Paramagnetic

2)

$\mathsf{[FeF_{6}] {}^{3 - } }$

Calculation of O.N. :-

→ x -1×6 = -3

→ x = 3

Electronic configuration of Fe

• $\mathsf{[Ar] 4s {}^{2} 3d {}^{6} }$

Then,

$\mathsf{Electronic \: configuration \: of \: Fe {}^{3 + } }</p><p>$

• $\mathsf{[Ar] 3d {}^{5} }$

Orbital diagram :-

( Refer to the attachment. )

Hence,

Magnetic character :- Paramagnetic

3)

$\mathsf{[Co(NH_{3})_{6}] {}^{3 + } }$

Calculation of O.N. :-

→ x + 0×6 = 3

→ x = 3

Electronic configuration of Co

• $\mathsf{[Ar] 4s {}^{2} 3d {}^{7} }$

Then,

$\mathsf{Electronic \: configuration \: of \: Co {}^{3 + } }$

• $\mathsf{[Ar] 3d {}^{6} }$

Orbital diagram :-

( Refer to the attachment. )

Hence,

Magnetic character :- Diamagnetic

4)

$\mathsf{[Fe(H_{2}O)_{6}] {}^{3 + } }$

Calculation of O.N. :-

→ x + 0×6 = 3

→ x = 3

Electronic configuration of Fe

• $\mathsf{[Ar] 4s {}^{2} 3d {}^{6} }$

Then,

$\mathsf{Electronic \: configuration \: of \: Fe {}^{3 + } }$

• $\mathsf{[Ar] 3d {}^{5} }$

Orbital diagram :-

( Refer to the attachment. )

Hence,

Magnetic character :- Paramagnetic

Therefore,

Option C is correct.