/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 190 Out of the following, the alkene... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 23: Problem 190

Out of the following, the alkene that exhibits optical isomerism is (a) 3 - methyl \(-2\) - pentene (b) 4 - methyl \(-1\) - pentene (c) 3 - methyl \(-1\) - pentene (d) 2- methyl \(-2\) - pentene

Short Answer

Expert verified
The alkene that exhibits optical isomerism is (a) 3-methyl-2-pentene.

Step by step solution

01

Understand Optical Isomerism

Optical isomerism occurs when there is a chiral center in a molecule. A chiral center is typically a carbon atom bonded to four different groups. This asymmetry allows the molecule to have non-superimposable mirror images, known as enantiomers.
02

Analyze the Given Alkenes for Chirality

For each provided alkene, identify potential chiral centers. A chiral center is absent in small alkenes with symmetry or identical substituents. Check each alkene structure to locate carbons that may have four different substituents.
03

Evaluate 3-methyl-2-pentene

- Structure: CH3-CH=C(CH3)-CH2-CH3 - Check: The carbon labeled C2 has different groups attached (H, CH3, ethyl group), making it a potential chiral center. Therefore, 3-methyl-2-pentene has chiral carbon.
04

Evaluate 4-methyl-1-pentene

- Structure: CH3-CH2-CH(CH3)-CH=CH2 - Check: The carbon labeled C4 (CH3-CH(CH3)-) is not a chiral center as it doesn't have four different groups; it has two hydrogen atoms.
05

Evaluate 3-methyl-1-pentene

- Structure: CH3-CH=C(CH3)-CH2-CH3 - Check: Similar to 3-methyl-2-pentene, but without making C2 a chiral center since one of the double-bonded carbons can't form four bonds.
06

Evaluate 2-methyl-2-pentene

- Structure: CH3-C(CH3)=C(CH3)-CH2-CH3 - Check: This structure has no carbon with four different substituents, thus lacks any chiral center.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Chiral Center
A chiral center is like the heart of optical isomerism. Imagine you're holding a carbon atom with arms stretching out in four different directions, each holding a different object. This means the carbon is attached to four unique groups.
A chiral center makes your molecule like a pair of left and right hands. Even if they look similar, you can't perfectly overlay one on the other. Such non-superimposable mirror images are what we call enantiomers. The ability to have these mirror images is what gives rise to optical isomerism.
  • Look for carbon atoms bonded to four different atoms or groups.
  • This unique arrangement is essential for chirality and hence optical activity.
  • If any two groups attached to the carbon are the same, it is not a chiral center.
Alkenes
Alkenes are hydrocarbons that include at least one carbon-carbon double bond. The presence of a double bond influences the geometry and chemistry of the molecule. When identifying a chiral center in alkenes, the double bond restricts rotation, which affects the spatial arrangement of attached groups.
However, a chiral center is less common in simple alkenes because the carbon atoms participating in the double bond can only attach to three different groups.
Alkenes carry:
  • At least one carbon-carbon double bond.
  • A tendency to be non-chiral due to the double-bonded carbons having fewer different substituents.
When assessing optical isomerism in alkenes, look for neighboring carbons that can form chiral centers rather than the carbons in the double bond itself.
Enantiomers
Enantiomers are mirror-image molecules that cannot be superimposed on one another, much like our left and right hands. They are a result of chiral centers in molecules.
The key characteristics of enantiomers include:
  • Identical physical properties (like melting point and boiling point).
  • Different interaction with polarized light; they rotate plane-polarized light in opposite directions.
  • Potentially very different effects in biological systems due to how they interact with other chiral molecules (like enzymes or receptors).
In summary, the presence of a chiral center leads to the formation of enantiomers, each having equal but opposite optical activity. Identifying enantiomers within alkenes relates directly to finding chiral centers, which often requires looking beyond the double bonded carbons to other parts of the molecule.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

How many stereoisomers are there for tartaric acid? (a) 3 (b) 4 (c) 5 (d) 0

The compound with an isopropyl group is (a) \(2,2,3,3\)-tetramethylpentane (b) 2,2 -dimethylpentane (c) \(2,2,3\)-trimethylpentane (d) 2-methylpentane

The hybridization of carbon atoms in C-C single bond of \(\mathrm{HC} \equiv \mathrm{C}-\mathrm{CH}=\mathrm{CH}_{2}\) is (a) \(\mathrm{sp}^{3}-\mathrm{sp}^{3}\) (b) \(\mathrm{sp}^{2}-\mathrm{sp}^{3}\) (c) \(\mathrm{sp}^{2}-\mathrm{sp}\) (d) \(\mathrm{sp}^{3}-\mathrm{sp}\)

Which of the following is optically active? (a) butane (b) 2 -methylpentane (c) 4-methylpentane (d) 3-methylheptane

Which of the following does not show geometrical isomerism? (a) 1,1 -dichloro-1-pentene (b) 1,2 -dichloro- 1 -pentene (c) 1,3 -dichloro-1-pentene (d) 1,4 -dichlroro-2-pentene
See all solutions

Recommended explanations on Chemistry Textbooks

The Earths Atmosphere

Read Explanation

Chemistry Branches

Read Explanation

Chemical Reactions

Read Explanation

Nuclear Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Inorganic Chemistry

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.