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.
41.
What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid?
A
$$C{r^{3 + }}$$ and $$C{r_2}O_7^{2 - }$$ are formed.
B
$$C{r_2}O_7^{2 - }$$ and $${H_2}O$$ are formed.
C
$$CrO_4^{2 - }$$ is reduced to +3 state of $$Cr.$$
D
$$CrO_4^{2 - }$$ is oxidised to +7 state of $$Cr.$$
Answer :
$$C{r_2}O_7^{2 - }$$ and $${H_2}O$$ are formed.
Dilute nitric acid converts chromate into dichromate and $${H_2}O.$$
$$2{K_2}Cr{O_4} + 2HN{O_3} \to $$ $${K_2}C{r_2}{O_7} + 2KN{O_3} + {H_2}O$$
42.
Ammonium dichromate is used in some fireworks.The green coloured powder blown in the air is
A
$$Cr{O_3}$$
B
$$C{r_2}{O_3}$$
C
$$Cr$$
D
$$CrO\left( {{O_2}} \right)$$
Answer :
$$C{r_2}{O_3}$$
\[{{\left( N{{H}_{4}} \right)}_{2}}C{{r}_{2}}{{O}_{7}}\xrightarrow{\Delta }\] \[\underset{\left( \text{green} \right)}{\mathop{C{{r}_{2}}{{O}_{3}}}}\,+{{N}_{2}}+4{{H}_{2}}O\]
Hence green coloured powder blown in the air is $$C{r_2}{O_3}.$$
43.
In which of the following compounds, transition metal has zero oxidation state?
A
$$Fe{\left( {CO} \right)_5}$$
B
$$N{H_2}.N{H_2}$$
C
$$NOCl{O_4}$$
D
$$Cr{O_5}$$
Answer :
$$Fe{\left( {CO} \right)_5}$$
Oxidation state of $$Fe$$ in $$Fe{\left( {CO} \right)_5}$$ is zero because $$CO$$ is a neutral ligand and it shows zero oxidation state. NOTE
In metal carbonyls, oxidation state of metal is always zero.
44.
The number of water molecules(s) not coordinated to copper ion directly in $$CuS{O_4}\,.5{H_2}O,\,{\text{is}}:$$
A
$$2$$
B
$$3$$
C
$$1$$
D
$$4$$
Answer :
$$1$$
In $$CuS{O_4}\,.5{H_2}O,$$ four $${H_2}O$$ molecules are directly coordinated to the central metal ion while one $${H_2}O$$ molecule is hydrogen bonded.
45.
Iron exhibits $$ + 2$$ and $$ + 3$$ oxidation states. Which of the following statements about iron is incorrect?
A
Ferrous oxide is more basic in nature than the ferric oxide.
B
Ferrous compounds are relatively more ionic than the corresponding ferric compounds.
C
Ferrous compounds are less volatile than the corresponding ferric compounds.
D
Ferrous compounds are more easily hydrolysed than the corresponding ferric compounds.
Answer :
Ferrous compounds are more easily hydrolysed than the corresponding ferric compounds.
$$F{e^{3 + }}$$ is easily hydrolysed than $$F{e^{2 + }}$$ due to more positive charge.
46.
The actinoids exhibit more number of oxidation states in general than the lanthanoids. This is because
A
the $$5f$$ orbitals extend further from the nucleus than the $$4f$$ orbitals
B
the $$5f$$ orbitals are more buried than the $$4f$$ orbitals
C
there is a similarity between $$4f$$ and $$5f$$ orbitals in their angular part of the wave function
D
the actinoids are more reactive than the lanthanoids.
Answer :
the $$5f$$ orbitals extend further from the nucleus than the $$4f$$ orbitals
NOTE: More the distance between nucleus and outer orbitals, lesser will be force of attraction on them. Distance between nucleus and $$5f$$ orbitals is more as compared to distance between $$4f$$ orbital and nucleus. So actinoids exhibit more number of oxidation states in general than the lanthanoids.
47.
Which of the following is not an amphoteric ion?
A
$$A{l^{3 + }}$$
B
$$C{r^{3 + }}$$
C
$$F{e^{2 + }}$$
D
$$Z{n^{2 + }}$$
Answer :
$$F{e^{2 + }}$$
No explanation is given for this question. Let's discuss the answer together.
48.
The radius of $$L{a^{3 + }}$$ (Atomic number of $$La = 57$$ ) is $$1.06\mathop {\text{A}}\limits^o .$$ Which one of the following given values will be closest to the radius of $$L{u^{3 + }}$$ (Atomic number of $$Lu = 71$$ )?
49.
Generally transition elements form coloured salts due to the presence of unpaired electrons. Which of the following compounds will be coloured in
solid state?