What is hyperconjugation ?

Hi Salha,

Hyperconjugation is a phenomenon which involves the delocalisation of σ − electrons to C − H bond of an alkyl group directly attached to an unsaturated system or to an atom with an unshared p-orbital (shown in figure)
For example: the hyperconjugation in ethyl cation can be shown as follows.

Hope, this answer is clear to you.

Best wishes!