$$\eqalign{
& {C_{{\text{excited}}\,\,{\text{state}}}} = 2{s^1}2p_x^1p_y^1p_z^1 \cr
& {O_{{\text{ground}}\,\,{\text{state}}}} = 2{s^2}2p_x^2p_y^1p_z^1 \cr} $$
In carbon dioxide $$C$$ is $$sp$$ hybridised and $$O$$ is $$s{p^2}$$ hybridised. $$sp$$ hybridised orbitals of carbon atom overlap with two $$p$$ orbitals of two oxygen atoms to form 2 $$sigma$$ bond and remaining $$p$$ - electrons ( unhybridised $$p$$ - orbital ) will be used to form $$pi$$ bonds.
212.
Which of the following statements is true about hybridisation?
A
The hybridised orbitals have different energies for each orbital.
B
The number of hybrid orbitals is equal to the number of atomic orbitals that are hybridised.
C
Hybrid orbitals form multiple bonds.
D
The orbitals with different energies undergo hybridisation.
Answer :
The number of hybrid orbitals is equal to the number of atomic orbitals that are hybridised.
NOTE : Greater the difference between electronegativities of two covalently bonded atoms more will be strength of hydrogen bond.
∴ $$F - H......F$$ bond is strongest due to largest difference in electronegativity of atoms and smallest size of $$F$$ atom.
214.
What is the formal charge on carbon atom in the following two structures :
According to $$VSEPR$$ theory repulsion order
$$lp - lp > lp - bp > bp - bp$$ Key Idea As the number of lone pairs of electrons increases, bond angle decreases due to repulsion between $$lp - lp.$$ Moreover, as the electronegativity of central atom decreases, bond angle decreases.
Hence, the order of bond angle is
( $$Cl$$ is less electronegative as compared to $$O$$ ).
218.
Among the following ions the $$p\pi - d\pi $$ overlap could be present in
In $$P–O$$ bond, $$\pi $$ bond is formed by the sidewise overlapping of $$d$$ - orbital of $$P$$ and $$p$$-orbital of oxygen. Hence it is formed by
$$p\pi $$ and $$d\pi $$ overlapping.
219.
Among $$LiCl,BeC{l_2},BC{l_3}$$ and $$CC{l_4},$$ the covalent bond character follows the order
The electronegativity increases from left to right in any period, so the electronegativity follows the order
$$Li < Be < B < C$$
and hence, the covalent character of chlorides of these elements increase from $$Li$$ to $$C$$ because size of cation left to right decreases and according to Fajans’ rule covalent character increases.
220.
Which of the following statements is not true?
A
Intermolecular hydrogen bonds are formed between two different molecules of compounds.
B
Intramolecular hydrogen bonds are formed between two different molecules of the same compound.
C
Intramolecular hydrogen bonds are formed within the same molecule.
D
Hydrogen bonds have strong influence on the physical properties of a compound.
Answer :
Intramolecular hydrogen bonds are formed between two different molecules of the same compound.