Rank the hydrogen atoms $(H_a, H_b, H_c)$ in the following molecule according to their acidic strengths.

Which of the following has a hyperconjugation effect?

The correct order for the rate of decarboxylation of the following compounds with sodalime will be:

In compound $(X)$,hyperconjugation is present and in $(Y)$,resonance effect is present. What are $X$ and $Y$,respectively?

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.

The nitration will mainly take place at position $.$