Which one of the nitrogen atoms in $H_2N-NH-CO-NH_2$ (where the atoms are labeled $I, II, III$ as shown in the structure) is the most nucleophilic?

Which pair of groups exhibits the $(-I)$ effect?

Which one of the following is not true regarding electromeric effect?

State True or False for the following statements:
$(i)$ The stability is explained by resonance effect and hyperconjugation.
$(ii)$ The resonance structures are drawn in resonance and hyperconjugation.
$(iii)$ Hyperconjugation is a bondless resonance.
$(iv)$ In resonance structure,there is movement of electron pair of only $\pi$ bond.

Which acid of each pair shown here would you expect to be stronger?
$(i)$ $CH_3CO_2H$ or $CH_2FCO_2H$
$(ii)$ $CH_2FCO_2H$ or $CH_2ClCO_2H$
$(iii)$ $CH_2FCH_2CH_2CO_2H$ or $CH_3CHFCH_2CO_2H$
$(iv)$ $F_3C-C_6H_4-COOH$ or $H_3C-C_6H_4-COOH$

Among the following sets,the most stable ionic species are