Question

Rank the alkenes from most stable to least stable.

1) 1. 1-butene, 2-butene, 2-methyl-2-butene
2) 2. 2-butene, 1-butene, 2-methyl-2-butene
3) 3. 2-methyl-2-butene, 2-butene, 1-butene
4) 4. 2-methyl-2-butene, 1-butene, 2-butene

Answer 1

The alkenes can be ranked for stability based on the number of alkyl substituents on the double bond: tetrasubstituted (most stable), disubstituted, and monosubstituted (least stable). Thus, the order is 2-methyl-2-butene (most stable), followed by 2-butene, and lastly 1-butene.

Step-by-step explanation:

To rank the alkenes from most stable to least stable we need to consider the stability factors, which include the degree of substitution of the double bond and the presence of steric hindrance or strain. The stability of alkenes typically increases with the number of alkyl substituents attached to the double-bonded carbons - tertiary being more stable than secondary, which in turn is more stable than primary.

Based on these principles, the correct order is:

1. 2-methyl-2-butene: This alkene is the most stable because it has a tetrasubstituted double bond.
2. 2-butene: This is the next most stable, having a disubstituted, trans double bond. Trans isomers are generally more stable than cis isomers in alkenes without additional steric hindrance.
3. 1-butene: This is the least stable among the ones listed, as it has a monosubstituted double bond.

Therefore, the most accurate ranking provided from the options given is 3) 2-methyl-2-butene, 2-butene, 1-butene.