The correct stability order of the following species is:

What is the order of $-I$ effect in orbitals?

Define the electromeric effect and describe its types.

With respect to the compounds $I-V$,choose the correct statement$(s)$.
$(A)$ The acidity of compound $I$ is due to delocalization in the conjugate base.
$(B)$ The conjugate base of compound $IV$ is aromatic.
$(C)$ Compound $II$ becomes more acidic,when it has a $-NO_2$ substituent.
$(D)$ The acidity of compounds follows the order $IV > V > I > II > III$.

Which among the following is an incorrect statement?

Which of the following electromeric effect representations is incorrect?