Among the following sets,the most stable ionic species are

The delocalization of $\sigma$ electrons of $C-H$ bond of an alkyl group with the $\pi$ electrons of benzene is observed in

Explain the electron displacement effects in covalent bonds.

Given below are two statements $:$
Statement $I :$ Hyperconjugation is not a permanent effect.
Statement $II :$ In general,greater the number of alkyl groups attached to a positively charged $C$ atom,greater is the hyperconjugation interaction and stabilization of the cation.
In the light of the above statements,choose the correct answer from the options given below

The correct order of the electron-donating or withdrawing effect (inductive/mesomeric effect) for the groups $-NH_2, -OCH_3, -C_6H_5$,and $-NO_2$ is:

In which $C-C$ bond of $CH_3-CH_2-CH_2-Br$,the inductive effect is expected to be the least?