31. Few compounds formed by chemical bonding are given below. Mark the incorrect example.
A
A molecule with central atom devoid of octet $$ - B{F_3}$$
B
A molecule with linear shape $$ - C{O_2}$$
C
A non-polar covalent compound between two different atoms $$ - C{H_4}$$
D
A molecule which is $$V$$ - shaped with a bond angle $${104.5^ \circ } - N{H_3}$$
Answer :
A molecule which is $$V$$ - shaped with a bond angle $${104.5^ \circ } - N{H_3}$$
32. In an octahedral structure, the pair of $$d$$ orbitals involved in $${d^2}s{p^3}$$ hybridization is
A
$${d_{{x^2} - {y^2},}}{d_{{z^2}}}$$
B
$${d_{xz,}}{d_{{x^2} - {y^2}}}$$
C
$${d_{{z^2},}}{d_{xz}}$$
D
$${d_{xy,}}{d_{yz}}$$
Answer :
$${d_{{x^2} - {y^2},}}{d_{{z^2}}}$$
33. How many $$sigma$$ and $$pi$$ bonds are present in toluene?
A
$$10\,\sigma $$ and $${\text{3}}\,\pi $$ bonds
B
$$12\,\sigma $$ and $${\text{3}}\,\pi $$ bonds
C
$$15\,\sigma $$ and $${\text{3}}\,\pi $$ bonds
D
$$6\,\sigma $$ and $${\text{3}}\,\pi $$ bonds
Answer :
$$15\,\sigma $$ and $${\text{3}}\,\pi $$ bonds
34. In the reaction $$2PC{l_5} \rightleftharpoons PCl_4^ + + PCl_6^ - ,$$ the change in hybridisation is from
A
$$s{p^3}d\,{\text{to}}\,s{p^3}\,{\text{and}}\,{\text{s}}{p^3}{d^2}$$
B
$$s{p^3}d\,{\text{to}}\,s{p^2}\,{\text{and}}\,{\text{s}}{p^3}$$
C
$$s{p^3}d\,{\text{to}}\,s{p^3}{d^2}\,{\text{and}}\,{\text{s}}{p^3}{d^3}$$
D
$$s{p^3}{d^2}\,{\text{to}}\,s{p^3}\,{\text{and}}\,{\text{s}}{p^3}d$$
Answer :
$$s{p^3}d\,{\text{to}}\,s{p^3}\,{\text{and}}\,{\text{s}}{p^3}{d^2}$$
35. In which of the following pairs of molecules/ions, both the species are not likely to exist?
A
$$H_2^ + ,He_{2\,\,\,\,}^{2 - }$$
B
$$H_2^ - ,He_2^{2 - }\,$$
C
$$H_2^{2 + },H{e_2}$$
D
$$H_2^ - ,He_2^{2 + }$$
Answer :
$$H_2^{2 + },H{e_2}$$
36. Element $$X$$ is strongly electropositive and element $$Y$$ is strongly electronegative. Both are univalent. The compound formed would be
A
$${X^ + }{Y^ - }$$
B
$${X^ - }{Y^{ + \,}}$$
C
$$X - Y$$
D
$$X \to Y$$
Answer :
$${X^ + }{Y^ - }$$
37. The correct sequence of bond length in single bond, double bond and triple bond of $$C$$ is
A
$$\left( {C - C} \right) = \left( {C = C} \right) = \left( {C \equiv C} \right)$$
B
$$C \equiv C < C = C < C - C$$
C
$$C - C < C = C < C \equiv C$$
D
$$C = C < C \equiv C < C - C$$
Answer :
$$C \equiv C < C = C < C - C$$
38.
Which of the following is the most stable state when two atoms come closer to each other to form a molecule?
A
(i), when the bond is formed, the energy is minimum.
B
(ii), when the atoms touch each other, the energy is zero.
C
(iii), when the atoms are isolated, the energy is minimum.
D
(ii), when the attractive forces are more than repulsive forces.
Answer :
(i), when the bond is formed, the energy is minimum.
39. In $$X - H - - - Y,X$$ and $$Y$$ both are electronegative elements, then
A
electron density on $$X$$ will increase and on $$H$$ will decrease
B
in both electron density will increase
C
in both electron density will decrease
D
on $$X$$ electron density will decrease and on
$$H$$ increase
Answer :
electron density on $$X$$ will increase and on $$H$$ will decrease
40. Which of the following is not isostructural with $$SiC{l_4}?$$
A
$$SC{l_4}$$
B
$$SO_4^{2 - }$$
C
$$PO_4^{3 - }$$
D
$$NH_4^ + $$
Answer :
$$SC{l_4}$$