D and F Block Elements MCQ Questions & Answers in Inorganic Chemistry | Chemistry
Learn D and F Block Elements MCQ questions & answers in Inorganic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
291.
In the following transition metals, the maximum number of oxidation states are exhibited by
A
chromium $$(Z = 24)$$
B
manganese $$(Z = 25)$$
C
iron $$(Z = 26)$$
D
titanium $$(Z = 22)$$
Answer :
manganese $$(Z = 25)$$
Manganese shows maximum number of oxidation states because it has 5 unpaired electrons in 3$$d$$ and also contains 2 electrons in 4$$s$$ sub-shell.
+2 +3 +4 +5 +6 +7
Other given metals show the following oxidation states
$$ Cr $$ = +2 +3 +4 +5 +6
$$ Fe $$ = +2 +3
$$ Ti $$ = +2 +3 +4
292.
Which of the following statements concerning lanthanide elements is false?
A
All lanthanides are highly dense metals.
B
Most characteristic oxidation state lanthanide elements is +3.
C
Lanthanides are separated from one another by ion exchange method.
D
Ionic radii of trivalent lanthanides steadily increases with increase in the atomic number.
Answer :
Ionic radii of trivalent lanthanides steadily increases with increase in the atomic number.
Ionic radii of trivalent lanthanides decrease with increase in atomic number.
293.
Which one of the following is diamagnetic ion?
A
$$C{o^{2 + }}$$
B
$$C{u^{2 + }}$$
C
$$M{n^{2 + }}$$
D
$$S{c^{3 + }}$$
Answer :
$$S{c^{3 + }}$$
$$S{c^{3 + }}$$ is diamagnetic as it does not contain any unpaired electron while others contain.
294.
Acidified potassium dichromate reacts with potassium iodide and oxidises it to$${I_2}.$$ What is the oxidation state of chromium in the products of the reaction?
A
+4
B
+6
C
+3
D
+2
Answer :
+3
During the reaction $${K_2}C{r_2}{O_7}$$ is converted to $$C{r_2}{\left( {S{O_4}} \right)_3}$$
$${K_2}C{r_2}{O_7} + 7{H_2}S{O_4} + 6KI \to $$ $$4{K_2}S{O_4} + C{r_2}{\left( {S{O_4}} \right)_3} + 7{H_2}O + 3{I_2}$$
$${\text{In}}\,\,{\text{C}}{{\text{r}}_2}{\left( {S{O_4}} \right)_3},O.S.\,\,{\text{of}}\,\,Cr\,\,{\text{is}}\, + 3.$$
295.
An aqueous solution of $$FeS{O_4},A{l_2}{\left( {S{O_4}} \right)_3}$$ and chrome alum is heated with excess of $$N{a_2}{O_2}$$ and filtered. The materials obtained are :
A
a colourless filtrate and a green residue
B
a yellow filtrate and a green residue
C
a yellow filtrate and a brown residue
D
a green filtrate and a brown residue
Answer :
a yellow filtrate and a brown residue
TIPS/FORMULAE:
Chrome alum is $${K_2}S{O_4}.C{r_2}{\left( {S{O_4}} \right)_3}.24{H_2}O$$
The filtrate is yellow due to $$CrO_4^{2 - }$$ ion and residue is brown due to $$Fe{\left( {OH} \right)_3}.$$
296.
Of the following outer electronic configurations of atoms, the highest oxidation state is achieved by which one of them?
A
$$\left( {n - 1} \right){d^3}\,n{s^2}$$
B
$$\left( {n - 1} \right){d^5}\,n{s^1}$$
C
$$\left( {n - 1} \right){d^8}\,n{s^2}$$
D
$$\left( {n - 1} \right){d^5}\,n{s^2}$$
Answer :
$$\left( {n - 1} \right){d^5}\,n{s^2}$$
$$\left( {n - 1} \right){d^5}\,n{s^2}$$ attains the maximum $$O.S.\,{\text{of}}\, + 7$$
297.
Fill the missing products in the following reactions.
$$\left( {\text{i}} \right)2MnO_4^ - + 16{H^ + } + 10{I^ - } \to $$ $$2M{n^{2 + }} + 8{H_2}O + \underline {\left( {\text{i}} \right)} $$
$$\left( {{\text{ii}}} \right)2MnO_4^ - + {H_2}O + {I^ - } \to $$ $$2Mn{O_2} + 2O{H^ - } + \underline {\left( {{\text{ii}}} \right)} $$
(i) and (ii) are respectively?
A
$$HI\,\,{\text{and}}\,\,{I_2}$$
B
$${I_2}\,\,{\text{and}}\,\,IO_3^ - $$
C
$${I_2}\,\,{\text{and}}\,\,{I_2}$$
D
$$IO_3^ - \,\,{\text{and}}\,\,{I_2}$$
Answer :
$${I_2}\,\,{\text{and}}\,\,IO_3^ - $$
No explanation is given for this question. Let's discuss the answer together.
298.
Which of the following metals corrodes readily in moist air?
A
Gold
B
Silver
C
Nickel
D
Iron
Answer :
Iron
Iron corrodes readily in moist air because iron is more reactive than $$Ni, Au$$ and $$Ag.$$ In other words the reduction potential of iron is very less, so its oxidation takes place readily.
299.
Which one of the following statements related to lanthanons is incorrect?
A
Europium shows + 2 oxidation state
B
The basicity decreases as the ionic radius decreases from $$Pr$$ to $$Lu$$
C
All the lanthanons are much more reactive than aluminium
D
$$Ce (+4)$$ solution are widely used as oxidising agent in volumetric analysis
Answer :
All the lanthanons are much more reactive than aluminium
$$Eu\left( {63} \right) = 4{f^7} \cdot 5{d^0},6{s^2},E{u^{2 + }} = 4{f^7}$$
In lanthanoids series, ionic radius decreases and covalent character increases, thus basicity decreases. Lanthanons are less reactive than aluminium due to high ionisation potential. The reason for this high ionisation potential is lanthanoid contraction. $$C{e^{4 + }}$$ is a good oxidising agent, it is easily converted to $$C{e^{3 + }}$$
300.
Which of the following oxides of manganese is amphoteric ?
A
$$Mn{O_2}$$
B
$$M{n_2}{O_3}$$
C
$$M{n_2}{O_7}$$
D
$$MnO$$
Answer :
$$Mn{O_2}$$
The more the oxidation state, the more is the acid character, $$MnO,M{n_2}{O_3}$$ are basic, $$Mn{O_2}$$ is amphoteric and $$M{n_2}{O_7}$$ is acidic.