Common Misconceptions
3 min read

Some P-Block Elements

- Let's bust some of the common misconceptions from this chapter.
Bridge bonding is a type of backbonding?
If you think that backbonding and bridge bonding are the same things, then you are right!
Backbonding is a type of bonding that occurs between atoms in a compound in which one atom has a filled orbital and the other has a vacant orbital as in .
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In fact, the bonding in diborane popularly known as bridge or banana bonding is a type of back bonding.
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Relative Lewis Acidic Character of Boron Halides
The book states that the relative lewis acidic strength of boron halides increases as we move down the group. This is reverse of what we would expect on the basis of electronegativity.
This can be easily explained on the basis of back bonding. The halogen atom has the tendency to back donate its lone pair to the empty p-orbital of boron atom through p-p bonding.
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In the case of , where the size of vacant 2p-orbital of boron and the filled 2p-orbital of fluorine are the same, back donation is possible. This backbonding makes less electron deficient and therefore, is a weak Lewis acid.
But as the size of halogen atom increases fron Cl to I, extent of overlap between 2p orbital of boron and bigger p-orbital of halogen decreases and consequently electron deficiency of B increases and so, the lewis acid character increases.
The order of increasing lewis character of boron halides
Dry ice makes the cloth wet!
We are probably aware that dry ice is solid carbon dioxide. This is the soft snow like substance which is used as a refrigerant for ice-creams or frozen food. But there can be a misconception that if it's an ice then on melting it will definitely make our clothes wet.
But wait wait....
The name "dry ice" itself suggests that it will be dry. In fact, dry ice does not melt into its liquid form, it sublimes or directly changes into vapour.
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