Chemistry - GOC Question with Solution | TestHub

(i) Imidazole has 6 π electrons ($\mathrm{C}=\mathrm{C}$, $\mathrm{C}=\mathrm{N}$ and the N-H lone pair). (ii) Pyrazine has 6 π electrons (three ring π bonds; the N lone pairs lie in the plane). (iii) 1,4-Dihydropyrazine has 8 π electrons (2 $\mathrm{C}=\mathrm{C}$ + 2 N lone pairs) : anti-aromatic. So i and ii.