/*! 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} Q45P (A true story) The manager of an... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 20: Q45P (page 1078)

(A true story) The manager of an organic chemistry stockroom prepared unknowns for鈥淜etones and Aldehydes鈥� experiment by placing two drops of the liquid unknowns in test tubes and storing the test tubes for several days until they were needed. One of the unknowns was misidentified by every student. This unknown was taken from a bottle marked 鈥淗eptaldehyde.鈥� The stockroom manager took an IR spectrum of the liquid in the bottle and found a sharp carbonyl stretch around and small, sharp peaks around 2710 and . The students complained that their spectra showed no peaks at 2710 or , but a broad absorption centered over the region and a carbonyl peak around . They also maintained that their samples are soluble in dilute aqueous sodium hydroxide.

(a)Identify the compound in the stockroom manager鈥檚 bottle and the compound in the students鈥� test tubes.

(b)Explain the discrepancy between the stockroom manager鈥檚 spectrum and the students鈥� results.

(c)Suggest how this misunderstanding might be prevented in the future.

Short Answer

Expert verified

(a)

(b) The difference between the two samples is one is aldehyde and another is a carboxylic acid.

(c) The problem can be prevented by keeping in an inert atmosphere or preparing fresh unknown samples.

Step by step solution

01

About heptaldehyde

The organic compound that bears seven carbons in the parent chain with the aldehyde group is heptaldehyde.There are some wavelength values for the identification of such compounds when they are present with substituents.

02

(a) About the structures

The structure in the stock bottle consists of an aldehyde group. The structure is shown below.

The structure in the student鈥檚 sample contains the carboxylic acid group. The structure is given below.

03

(b) About the difference

The student sample structure has carboxylic acid and the stock bottle contains aldehyde. The contact with oxygen present in the air gets oxidized to the highly sensitive aldehyde group to acid conversion.

04

(c) About the prevention

The prevention can be done by storing the aldehyde in an inert atmosphere for example nitrogen or argon, which will prevent oxidation reaction. Also, the preparation of fresh unknowns will help in the prevention.

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!

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

Question: Predict the products (if any) of the following acid-base reactions.

  1. formic acid + ammonia
  2. terphthalic acid + excess NaOH
  3. p-toluic acid + sodium trifluoroacetate
  4. 伪-chloropropionic acid + sodium propionate
  5. benzoic acid + potassium phenoxide

Predict the major products formed when the following amines undergo exhaustive methylation, treatment with Ag2O, and heating.

  1. Hexan-2-amine
  2. 2-methylpiperidine
  3. N-ethylpiperidine

5.

6.

Glutathione (GSH) is a tripeptide that serves as a mild reducing agent to detoxify peroxides and maintain the cysteine residues of hemoglobin and other red blood cell proteins in the reduced state. Complete hydrolysis of glutathione gives Gly, Glu, and Cys. Treatment of glutathione with carboxypeptidase gives glycine as the first free amino acid released. Treatment of glutathione with 2,4-dinitrofluorobenzene (Sanger reagent, Problem 24-21, page 1282), followed by complete hydrolysis, gives the 2,4-dinitrophenyl derivative of glutamic acid. Treatment of glutathione with phenyl isothiocyanate does not give a recognizable phenylthiohydantoin, however.

(a) Propose a structure for glutathione consistent with this information. Why would glutathione fail to give a normal product from Edman degradation, even though it gives a normal product from the Sanger reagent followed by hydrolysis?

(b) Oxidation of glutathione forms glutathione disulfide(GSSG). Propose a structure for glutathione disulfide, and write a balanced equation for the reaction of glutathione with hydrogen peroxide.

(a) Give the products expected when acetic formic anhydride reacts with

(i) aniline and

(ii) benzyl alcohol

(b) Propose mechanisms for these reactions.

Question: A carboxylic acid has two oxygen atoms, each with two nonbonding pairs of electrons.

  1. Draw the resonance forms of a carboxylic acid that is protonated on the hydroxy oxygen atom.
  2. Compare the resonance forms with those given previously for an acid protonated on the carbonyl oxygen atom.
  3. Explain why the carbonyl oxygen atom of a carboxylic acid is more basic than the hydroxy oxygen.
See all solutions

Recommended explanations on Chemistry Textbooks

Making Measurements

Read Explanation

Chemical Analysis

Read Explanation

Physical Chemistry

Read Explanation

Organic Chemistry

Read Explanation

Chemical Reactions

Read Explanation

The Earths Atmosphere

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.