Among the following,the most acidic compound is

Given below are two statements:
Statement $I$: In $O_2N-C_6H_4-CH^+-C_6H_4-OCH_3$, the carbocation is stabilised by $+R$ effect of $-OCH_3$ group.
Statement $II$: In $O_2N-C_6H_4-CH^--C_6H_4-OCH_3$, the carbanion is stabilised by $-R$ effect of $-NO_2$ group.
In the light of the above statements, choose the correct answer from the options given below:

Which of the following is not the correct order of inductive effect?

The hyperconjugative stabilities of tert-butyl cation and $2-$butene,respectively,are due to

The number of activating and deactivating groups among the following are respectively: $-OCH_2CH_3, -COCH_3, -NHCOCH_3, -COOCH_3, -SO_3H$

Choose the correct order $:-$