Question

arrange the following newman projections of butane in order of energy.

Explanation:

Step1: Understand steric hindrance

Steric hindrance increases energy. Larger groups in close - proximity raise energy.

Step2: Analyze IV

In IV (anti - conformation), methyl groups are far apart, lowest steric hindrance, lowest energy.

Step3: Analyze II

In II (gauche - conformation), one methyl - methyl interaction, more energy than IV.

Step4: Analyze III

In III (eclipsed with one H - CH₃ and two H - H eclipsing), more steric and torsional strain than II.

Step5: Analyze I

In I (fully eclipsed with two CH₃ - CH₃ eclipsing), highest steric and torsional strain, highest energy.

Answer:

IV<II<III<I