Which Alkene is capable of stereoisomerism: 1-pentene, 2-methyl-1-pentene, 2-methyl-2-pentene, 2-pentene, or 2,3-dimethyl-2-butene?

To determine which alkene is capable of stereoisomerism, we need to consider its structural characteristics. Stereoisomerism arises from the presence of double bonds, which limit the rotation around that bond, leading to different spatial arrangements of the substituent groups.

In this case, among the given options, the alkene 2,3-dimethyl-2-butene is capable of stereoisomerism. This is because it has two chiral centers, specifically at carbons 2 and 3, due to the presence of the methyl groups. The carbon-carbon double bond in 2,3-dimethyl-2-butene restricts the rotation around it, resulting in different spatial arrangements of the methyl groups.

On the other hand, the other alkenes mentioned, such as 1-pentene, 2-methyl-1-pentene, 2-methyl-2-pentene, and 2-pentene, do not have chiral centers or any other structural features that would lead to stereoisomerism.

Therefore, only 2,3-dimethyl-2-butene among the given options is capable of exhibiting stereoisomerism.