Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 10: Problem 111

The greater acidity of thiols compared to alcohols can be explained by the fact that sulfur (a third period element) is larger than oxygen (a second- period element). The negative charge on an alkylsulfide ion ( \(\left.\mathrm{RS}^{-}\right)\)is delocalized over a larger area and is therefore more stable than the negative charge on an alkoxide ion \(\left(\mathrm{RO}^{-}\right)\). Thiols are sufficiently strong acids so that when dissolved in aqueous sodium hydiroxide, they are converted completely to alkylsulfide salts.

Short Answer

Expert verified
Answer: Thiols are more acidic than alcohols because the larger sulfur atom can better accommodate and delocalize a negative charge in the conjugate base (alkylsulfide ion) compared to the oxygen atom in alcohols. When thiols react with aqueous sodium hydroxide, they form alkylsulfide salts and water due to their higher acidity and complete reaction with the strong base.

Step by step solution

01

Understand the acidity difference between thiols and alcohols

Acidity of a compound depends on the stability of its corresponding conjugate base. In this case, we have a thiol (\(\mathrm{RSH}\)) and an alcohol (\(\mathrm{ROH}\)). When a thiol loses its proton, it forms an alkylsulfide ion (\(\mathrm{RS}^{-}\)), and when an alcohol loses its proton, it turns into an alkoxide ion (\(\mathrm{RO}^{-}\)). The stability of these ions determines the acidity of the respective compounds.
02

Explain the effect of atom size on the stability of ions

The larger the atom, the better it can accommodate a negative charge as it can be delocalized over a larger area. Since sulfur is larger than oxygen, the charge on the sulfur atom in the alkylsulfide ion (\(\mathrm{RS}^{-}\)) is delocalized over a larger area, making it more stable compared to the alkoxide ion (\(\mathrm{RO}^{-}\)). Therefore, the thiol (\(\mathrm{RSH}\)) is more acidic than alcohol (\(\mathrm{ROH}\)).
03

Describe the interaction between thiols and sodium hydroxide

Sodium hydroxide (\(\mathrm{NaOH}\)) is a strong base, which can react with thiols. The reaction can be represented as: \(\mathrm{RSH + NaOH \to RS^{-}Na^{+} + H_{2}O}\) Since thiols are sufficiently strong acids, they react completely with sodium hydroxide, resulting in alkylsulfide salts (\(\mathrm{RS^{-}Na^{+}}\)).

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

Chrysamehemic acid occurs as a mixture of esters in flowers of the chryxanthemum (pyrethrum) family. Reduction of charysanthemaic acid to its alcohol (Section 17.6A) followed by conversion of the alcohol to its tosylate gives charysaathemyl tosylate. Solvolysis (Section 9.2) of the tosylate gives a mixture of artemesia and yomogi alcobok.

Compounds containing hyklroxyl groups on two adjacent carhon atoms are called vicinal diols, or alternatively, glycols. Such compounds can be synthesized by a variety of methods, including oxidation of alkenes by \(\mathrm{OsO}_{4}\) (Section 6..a4). The products of arid-catalyzed dehydration of glycols are quite different from those of acid-ratalyzed dehydration of alcohols. For example, treating 2,3-dimethyl-2,3= butanediol (commonly called pinacol) with concentrated sulfuric acid gives 3,3= dimethyl 2 .butanone (commonly called pinacolone): CC(=O)C(C)(C)P 2,3-Dimethyl-2,3-butanediol 3,3-Dimethy-2-butanone (Pinacol) (Pimacolone)

Primary alcohols with extensive \(\beta\)-hranching give large amounts of a product erined from rearrangement. For example, treatment of 2,2 -dimethyl-1 propanol neopentyl alcohol) wìth HBr gives a rearranged product almost exclasively. \(10.5\) Cornersion of Alcohols to Haloakanes and sulfons CC(C)(C)CO CCC(C)(C)Br 2.2-Dimethyy-1-propanol 2-Bromo-2-tuetlyylbutane (a product of rearrangement)

When isomeric alkenes are obtained in acid catalyzed dehydration of an alcohol, the alkene having the greater number of substituents on the double bond (the more stable alkene) generally predominates (Zaitsev's rule, Section 9.5).

Thiols are much more acidic than alcohols.
See all solutions

Recommended explanations on Chemistry Textbooks

Inorganic Chemistry

Read Explanation

Organic Chemistry

Read Explanation

Chemical Analysis

Read Explanation

The Earths Atmosphere

Read Explanation

Kinetics

Read Explanation

Ionic and Molecular Compounds

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