Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 5: Question 5.33 (page 281)

(+)-Tartaric acid has a specific rotation of +12.0°. Calculate the specific rotation of a mixture of 68% (+)@tartaric acid and 32% (-)@tartaric acid.

Short Answer

Expert verified

Answer:

Specific rotation = 4.3

Step by step solution

01

Introduction

The optical purity of a mixture is defined as the ratio of its rotation to the rotation of a pure enantiomer. The enantiomeric excess (e.e.) is a more common method for expressing the relative amounts of enantiomers in a mixture. To compute the enantiomeric excess of a mixture, we calculate the excess of the predominant enantiomer as a percentage of the entire mixture.

02

Optical Rotation

o.p. = e.e. = |d-l|x 100%

|d+l|

(Where, o.p = optical purity, e.e=enantiomeric excess,d=68% and l=32%)

03

Enantiomeric excess

e.e = 68-32 x 100 = 36%

68+32

04

Optical rotation of mixture

Therefore,

Optical rotation of this mixture = 36% x (+12.0°)

= 4.3

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.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

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

For each Fischer projection, label each asymmetric carbon atom as (R) or (S). (a)-(f) the structures in Problem 5-18

Question: Draw all distinct stereoisomers for each structure. Show the relationships (enantiomers, diastereomers, etc.) between the isomers. Label any meso iosmers, and draw any mirror planes of symmetry.

(a) CH3 -CHCI-CHOH-COOH

(b) tartaric acid, HOOC-CHOH - CHOH-COOH

(c) HOOC -CHBr-CHOH- CHOH-COOH

(d)

(e)

Question: Draw three-dimensional representations of the following compounds. Which have asymmetric carbon atoms? Which have no asymmetric carbons but are chiral anyway? Use your models for parts (a) through (d) and any others that seem unclear.

(a) CICH = C = CHCI

1,3-dichloropropadiene

(b) CICH = C = CHCH3

1-chlorobuta-.1,2 diene

(c) CICH = C = CH =C(CH3)2

1-chloro-3-methyl uta-1,2-diene

(d) CICH = C = CH CH2

1-chlorobuta-.1,3-diene

(e)

(f)

(g)

The following structures are optically active compounds. Star (*) the asymmetric carbon atoms in these structures.

Question. For each structure,

  1. Draw all the stereoisomers.
  2. Label each structure as chiral or achiral.
  3. Give the relationships between the stereoisomers (enantiomers, diastereomers).
See all solutions

Recommended explanations on Chemistry Textbooks

Making Measurements

Read Explanation

Physical Chemistry

Read Explanation

Nuclear Chemistry

Read Explanation

Inorganic Chemistry

Read Explanation

Chemical Reactions

Read Explanation

Kinetics

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.

Sign-up for free