Which among the following pairs of electronic effect and its example is $NOT$ correct?

The higher stabilities of $tert$-butyl cation over isopropyl cation and $trans-2-butene$ over propene,respectively,are due to orbital interactions involving

Which of the following groups exhibits $(+)R$ effect?

Which of the following has a hyperconjugation effect?

State True or False for the following statements regarding the $-NO_2$ group in nitrobenzene:
$(i)$ In resonance,it acts as an electron-donating group,and in the inductive effect,it acts as an electron-attracting group.
$(ii)$ It acts as an electron-donating group in both resonance and the inductive effect.
$(iii)$ It acts as an electron-attracting group in both resonance and the inductive effect.
$(iv)$ It acts as an electron-attracting group in resonance and an electron-donating group in the inductive effect.

Explain the delocalization of electrons in $CH_3-CH_2^+$ and $CH_3-CH=CH_2$.