Chemical Bonding and Molecular Structure MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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171.
The correct order of the $$O - O$$ bond length in $${O_2},{H_2}{O_2}$$ and $${O_3}$$ is
A
$${O_2} > {O_3} > {H_2}{O_2}$$
B
$${O_3} > {H_2}{O_2} > {O_2}$$
C
$${O_2} > {H_2}{O_2} > {O_3}$$
D
$${H_2}{O_2} > {O_3} > {O_2}$$
Answer :
$${H_2}{O_2} > {O_3} > {O_2}$$
The bond length of $$O - O$$ in $${H_2}{O_2}$$ is $$147.5\,pm,$$ in $${O_3}$$ is $$128\,pm$$ and in $${O_2}$$ it is $$121\,pm,$$ so the correct order is $${O_2} < {O_3} < {H_2}{O_2}.$$
172.
The compound which contains both ionic and covalent bonds is
A
$$C{H_4}$$
B
$${H_2}$$
C
$$KCN$$
D
$$KCl$$
Answer :
$$KCN$$
In $$KCN,$$ ionic bond is present between $${K^ + }$$ and $$C{N^ - }$$ and covalent bonds are present between carbon and nitrogen $$C \equiv N$$ .
173.
The compound $$M{X_4}$$ is tetrahedral. The number of $$ < XMX$$ formed in the compound are
A
three
B
four
C
five
D
six
Answer :
six
three angle below $$M$$ and three above $$M$$ hence $$= 6$$
174.
Among the following, the pair in which the two species are not isostructural, is
A
$$Si{F_4}\,{\text{and}}\,S{F_4}$$
B
$$lO_3^ - \,{\text{and}}\,Xe{O_3}$$
C
$$BH_4^ - \,{\text{and}}\,NH_4^ + $$
D
$$PF_6^ - \,{\text{and}}\,S{F_6}\,$$
Answer :
$$Si{F_4}\,{\text{and}}\,S{F_4}$$
$$Si{F_4}$$ and $$S{F_4}$$ are not isostructural because $$Si{F_4}$$ is tetrahedral due to $$s{p^3}$$ hybridisation of $$Si.$$
$${}_{14}Si = 1{s^2},2{s^2},2{p^6},3{s^2}3{p^2}$$ ( in ground state )
$${}_{14}Si = 1{s^2},2{s^2}2{p^6},3{s^1}3{p^3}$$ ( in excited state )
Hence, four equivalent $$s{p^3}$$ hybrid orbitals are obtained and they are overlapped by four $$p - {\text{orbitals}}$$ of four fluorine atoms on their axis. Thus, it shows following structure:
While $$S{F_4}$$ is not tetrahedral but it is arranged in
trigonal bipyramidal geometry (has see saw shape) because in it $$S$$ is $$s{p^3}d$$ hybrid.
$${}_{16}S = 1{s^2},2{s^2}2{p^6},3{s^2}3p_x^23p_y^13p_z^1$$ ( in ground state )
$$ = 1{s^2},2{s^2}2{p^6},\underbrace {3{s^2}3p_x^13p_y^13p_z^13d_{xy}^1}_{s{p^3}d\,\,{\text{hybridisation}}}$$ ( in first excitation state )
Hence, five $$s{p^3}d$$ hybrid orbitals are obtained. One
orbital is already paired and rest four are overlapped with four $$p - {\text{orbitals}}$$ of four fluorine atoms on their axis in trigonal bipyramidal form.
This structure is distorted from trigonal bipyramidal to tetrahedral due to involvement of repulsion between lone pair and bond pair.
175.
Which of the following bond orders is indication of existence of a molecule?
A
Zero bond order
B
Negative bond order
C
Positive bond order
D
All of these
Answer :
Positive bond order
A molecule exists only if the bond order is positive. If bond order is zero or negative, the molecule does not exist.
176.
Which of the following shows $$ds{p^2}$$ hybridisation and a square planar geometry?
A
$$S{F_6}$$
B
$$Br{F_5}$$
C
$$PC{l_5}$$
D
$${\left[ {Ni{{\left( {CN} \right)}_4}} \right]^{2 - }}$$
178.
The correct order of bond lengths $$P, Q$$ and $$R$$ is
A
$$P > Q > R$$
B
$$R > Q > P$$
C
$$Q > P > R$$
D
$$Q > R > P$$
Answer :
$$P > Q > R$$
$$P$$ is related to $$s{p^3}$$ - hybridised $$C$$ - atom, $$Q$$ is related to $$s{p^2}$$ - hybridised $$C$$ - atom and $$R$$ is related to $$sp$$ - hybridised $$C$$ - atom.
179.
Given below is the bond angle in various types of hybridisation. Mark the bond angle which is not correctly matched.
A
$$ds{p^2} - {90^ \circ }$$
B
$$s{p^3}{d^2} - {90^ \circ }$$
C
$$s{p^3}d - {90^ \circ }$$
D
$$s{p^3} - {109.5^ \circ }$$
Answer :
$$s{p^3}d - {90^ \circ }$$
In $$s{p^3}d,$$ the bond angle is $${120^ \circ }$$ and $${90^ \circ }.$$
180.
Sulphur reacts with chlorine in 1 : 2 ratio and forms $$X.$$ Hydrolysis of $$X$$ gives a sulphur compound $$Y.$$ What is the hybridisation state of central atom in the compound.