Question

Rank by increasing stability. Why? S ww Rank by increasing stability why

Answer 1

ANSWER : i Stability order: A< <<< IV I I TIL This can be explained on the basis of angle strain is the ring. Angle strain = 1 (109.5" - bond angle) where bond angle for a polygon = 180' - 360° no of sides Bond angle – 180 - 360 = 60° & angle strain = 1 (109.5 -60°) = 24.75° In II; angle strain = 1 (109.5 -90) = 9.75° In II; angle strain = 2 (109.5 -108") = 0.75° ale strais in II is zero because cyclohexane assumes non-planar chair conformation.

angles are ; au bond 109.50 Now smaller the angle strain, the stability Hence, the above stability order. greater is. 1) Stability order: I This can be explained on the basis of van der Waals repulsions between methyl group & tert-butyl group ( called 1,3-diaxial interactions). In , both groups occupy axial positions, hence maximum repulsions. In I the smaller methyl group occupies favorable equatorial position & repulsions decrease. the bulky tert-butyl group goes to equatorial position & repulsions become minimum. In I, the bulky x