Arrange the following compounds in decreasing order of their relative stability based on the nature of their -systems: (i) CH ₂= C = CH ₂ (ii) CH ₂= CH - CH = CH ₂ (iii) CH ₂= CH - CH ₂- CH ₂- CH = CH ₂ (iv) C ₆ H ₆

Step-by-step solution

Compound (iv) is benzene, which is an aromatic compound. Aromaticity provides exceptional stability due to complete cyclic delocalization of -electrons. Compound (ii) is 1,3 -butadiene, a conjugated diene. Conjugation allows delocalization of -electrons over four carbon atoms, providing resonance energy and making it more stable than isolated dienes. Compound (iii) is 1,5 -hexadiene, an isolated diene. The two -bonds are separated by two single bonds, so there is no conjugation. It is less stable than conjugated di