The d- and f- Block Elements Test

Result

The d- and f- Block Elements Test - 76

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Which of the following has diamagnetic character?

A
$$[ NiCl_4]^{2-} $$

B
$$ [ CoF_6]^{3-} $$

C
$$ [Fe(H_2O)_6 ]^{2+} $$

D
$$ [Ni (CN)_4]^{2-} $$

Solution

$$ [ Ni(CN)_4]^{2-} \to Ni^{2+}\to [Ar]3d^8.$$ The pairing of electrons will take place as $$CN^-$$ is strong field ligand.

As $$ [ Ni(CN)_4]^{2-} $$ has no unpaired electron. It is diamagnetic.
Question 2
1 / -0

Which of the following complexes is diamagnetic?

A
$$Ni(CO)_4$$

B
$$Ni(Cl_4)^{2-}$$

C
$$Ni(Br)_4^{2-}$$

D
$$NiCl_2.4H_2O$$

Solution

$$CO$$ is a strong ligand so induce pairing of electrons and hence $$Ni(CO)_4$$ is diamagnetic.

$$Ni(CO)_4\to Ni^0\to [Ar]3d^84s^2$$

In the presence of strong field ligand pairing of electrons take place.

$$Ni^0\to [Ar]3d^{10}4s^0\to$$ so electrons of ligand will occupy 4s and 4p electrons.

So, there is no unpaired electrons making it diamagnetic.
Question 3
1 / -0

Cuprous ion is colourless, while cupric ion is coloured because

A
both have unpaired electrons in d -orbital

B
cuprous ion has a completed d-orbital and cupric ion has an incomplete d-orbital

C
both have half-filled p and d -orbitals

D
cuprous ion has incomplete d-orbital and cupric ion has a completed d -orbital

Solution

Cuprous ion is colourless, while cupric ion is coloured because cuprous ion has completely filled d-orbital and cupric ion has an incompletely filled d-orbital.

Cuprous ion $$ (Cu^+) \to [Ar]3d^{10} $$ zero unpaired electron

Cupric ion $$ (Cu^{2+}) \to [Ar]3d^{9} $$ one unpaired electron
Question 4
1 / -0

Wilkinson's catalyst used as a homogeneous catalyst in the hydrogenation of alkaline contains

A
Iron

B
Aluminium

C
Rhodium

D
Cobalt

Solution

Wilkinson's catalyst is Chlorotris(triphenylphosphine)rhodium(I) $$([Rh(PPh_3)_3Cl])$$. It contains Rh as the central metal atom.
Question 5
1 / -0

Reagent (E) is:

A
$$LAH$$

B
$$NaBH_4$$

C
$$H_2 / Ni$$

D
$$K + liq. NH_3$$ in $$EtOH$$

Solution

Hence, Option "C" is the correct answer.
Question 6
1 / -0

Ziegler-Natta catalysts

A
Are triethyl aluminium titanium tetrachloride complex$$(C_2H_3)Al + TiCl_4.$$

B
Are used to prepare stereospecific addition polymers

C
Are employed to have stereochemical control of the polymerisation process.

D
All the above

Solution
Question 7
1 / -0

Wilkinson's catalyst is used in

A
polymerization

B
condensation

C
halogenation

D
hydrogenation

Solution

Wilkinson's catalyst is used as homogeneous catalyst in the hydrogenation of alkenes and alkynes.

$$C_nH_{2n}+H_2\xrightarrow{catalyst} C_nH_{2n+2}$$
Question 8
1 / -0

Which of the following reagents can be used for the given reaction ?

A
$$i. D_2O / D_3O^\bigoplus \,ii. Cl_2 + AcOH \,iii. NaBH_4 / H_2O$$

B
$$i. Cl_2 + AcOH \,ii. D_2O \,iii. LAH / H_2O$$

C
$$ii. D_2O \,iii. HgCl_2 / CdCO_3 / H_2O$$

D
$$i. Base (PhLi), \,ii. HgCl_2 / CdCO_3-H_2O \, iii. D_2O$$

Solution

The $$(C=O)$$ group is protected by converting into cyclic thioacetal and then an organometallic base like $$PhLi$$ is used to generate carbanion followed by treatment with $$D_2O$$ to incorporate $$D$$. Finally, the aldehyde is regenerated.

Hence, Option "C" is the correct answer.
Question 9
1 / -0

Pick out wrong combination

A
$$Fe^{+2}\rightarrow Haemoglobin$$

B
$$Mg^{2+}\rightarrow Photosynthesis$$

C
$$Se^{2+}\rightarrow Kreb \ Cycle$$

D
$$CO^{+2}\rightarrow Vitamin \ B-12$$

Solution

Iron atom in the Haemoglobin of blood is in the +2 Oxidation state. ie., Iron is present as $$Fe^{2+}$$.

$$\text{Mg2+ is the central atom of the chlorophyll molecule,}$$ and fluctuations in its levels in the chloroplast regulate the activity of key photosynthetic enzymes. Relatively little is known of the proteins mediating Mg2+ uptake and transport in plants.

Cobalt is also an essential trace element for humans, and is found at the centre of vitamin B12 and a range of other co-enzymes called cobalamins.

and, in there is no involvement of $$Se^{2+}$$ in kreb cycle. Thus, wrong combination is C.
Question 10
1 / -0

Which of the following has maximum magnetic moment?

A
$${V}^{3+}$$

B
$${Cr}^{3+}$$

C
$${Fe}^{3+}$$

D
$${C}^{3+}$$