Explain hyperconjugation or no-bond resonance with an example.

(N/A) Hyperconjugation is a permanent electronic effect that involves the delocalization of $\sigma$ electrons of a $C-H$ bond of an alkyl group directly attached to an atom of an unsaturated system or to an atom with an unshared $p$-orbital.
It is also known as 'no-bond resonance' because the contributing structures do not involve a covalent bond between the carbon and the hydrogen atom.
Example: Hyperconjugation in ethyl cation $(CH_3-CH_2^+)$.
In the ethyl cation,the positively charged carbon atom has an empty $p$-orbital. One of the $C-H$ bonds of the methyl group can align in the plane of this empty $p$-orbital. The electrons of this $C-H$ bond are then delocalized into the empty $p$-orbital,resulting in the following contributing structures:
$(I) \leftrightarrow (II) \leftrightarrow (III) \leftrightarrow (IV)$
In these structures,the hydrogen atom is shown as $H^+$ without a bond to the carbon,which explains the term 'no-bond resonance'.