Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 4: Problem 4

Write an equation to show the proton transfer between each alkene or cycloalkene and HCl. Where two carbocations are possible, show each. (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}=\mathrm{CHCH}_{3}\) (b) C1=CCCCC1 2-Pentene Cyclohexene

Short Answer

Expert verified
Question: Write an equation for the proton transfer between each of the following alkenes/cycloalkenes and HCl, and show the possible carbocations that can be formed during the reaction: (a) 2-Pentene (b) Cyclohexene Answer: (a) For 2-Pentene, the proton transfer reaction with HCl is: CH3CH2CH=CHCH3 + HCl → CH3CH2CH+CH2CH3 + Cl-. The possible carbocations formed in this reaction are CH3CH2CH+CH2CH3 and CH3CH+CH2CH2CH3. (b) For Cyclohexene, the proton transfer reaction with HCl is: Cyclohexene + HCl → [Cyclohexyl carbocation] + Cl-. In this case, there is only one possible carbocation formed: [Cyclohexyl carbocation].

Step by step solution

01

(a) Proton transfer for 2-Pentene and HCl reaction

The first step is to break the double bond in 2-Pentene and show proton transfer with HCl. The resulting structure becomes a carbocation. The reaction is: \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}=\mathrm{CHCH}_{3} + \mathrm{HCl} \rightarrow \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}^{+}\mathrm{CH}_{2} \mathrm{CH}_{3} + \mathrm{Cl}^{-}\)
02

(a) Showing both carbocations for 2-Pentene/HCl reaction

Now, we need to show that the carbocation can also form on the other carbon atom adjacent to the double bond. The other possible carbocation is: \(\mathrm{CH}_{3} \mathrm{CH}^{+} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3} + \mathrm{Cl}^{-}\)
03

(b) Proton transfer for Cyclohexene and HCl reaction

The first step is to break the double bond in Cyclohexene and show proton transfer with HCl. The resulting structure becomes a carbocation. The reaction is: Cyclohexene + HCl \(\rightarrow\) [Cyclohexyl carbocation] + Cl^-
04

(b) Showing both carbocations for Cyclohexene/HCl reaction

In the case of Cyclohexene, there is only one possible carbocation because only one carbon atom is available adjacent to the double bond. This carbocation has already been presented in the previous step, and no additional carbocation structures are possible.

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

Answer True or False to the following statements about energy diagrams and reactions. (a) A reaction coordinate diagram is used to visualize the change in the internal energy of chemical structures that occurs during chemical reactions. (b) Thermodynamics is the study of the energies of structures that are represented by wells on reaction coordinate diagrams. (c) Kinetics is the study of the rates of chemical reactions. (d) One part of a reaction mechanism would be the understanding of which bonds break and form during a reaction. (e) Thermal reactions occur via collisions between molecules, and the more energy in those collisions the greater the rate of the reactions. (f) The enthalpy of a reaction is the sole determinant of whether it will or will not occur. (g) An exergonic reaction will always occur during the life span of the standard human being.

Complete a net ionic equation for each proton-transfer reaction using curved arrows to show the flow of electron pairs in each reaction. Label the original acid and its conjugate base; then label the original base and its conjugate acid. (a) \(\mathrm{NH}_{4}^{+}+\mathrm{OH}^{-} \rightleftharpoons\) (b) \(\mathrm{CH}_{3} \mathrm{COO}^{-}+\mathrm{CH}_{3} \mathrm{NH}_{3}^{+} \rightleftharpoons\) (c) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{O}^{-}+\mathrm{NH}_{4}^{+} \rightleftharpoons\) (d) \(\mathrm{CH}_{3} \mathrm{NH}_{3}^{+}+\mathrm{OH}^{-} \rightleftharpoons\)

Methyl isocyanate, \(\mathrm{CH}_{3}-\mathrm{N}=\mathrm{C}=\mathrm{O}\), is used in the industrial synthesis of a type of pesticide and herbicide known as a carbamate. As a historical note, an industrial accident in Bhopal, India, in 1984 resulted in leakage of an unknown quantity of this chemical into the air. An estimated 200,000 persons were exposed to its vapors, and over 2000 of these people died. (a) Write a Lewis structure for methyl isocyanate, and predict its bond angles. What is the hybridization of its carbonyl carbon? Of its nitrogen atom? (b) Methyl isocyanate reacts with strong acids, such as sulfuric acid, to form a cation. Will this molecule undergo protonation more readily on its oxygen or nitrogen atom? In considering contributing structures to each hybrid, do not consider structures in which more than one atom has an incomplete octet.

Which has the larger numerical value? (a) The \(\mathrm{p} K_{\mathrm{a}}\) of a strong acid or the \(\mathrm{p} K_{\mathrm{a}}\) of a weak acid (b) The \(K_{\mathrm{a}}\) of a strong acid or the \(K_{\mathrm{a}}\) of a weak acid

Benzoic acid, \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COOH}\left(\mathrm{p} K_{\mathrm{a}} 4.19\right)\), is only slightly soluble in water, but its sodium salt, \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COO}^{-} \mathrm{Na}^{+}\), is quite soluble in water. In which solution(s) will benzoic acid dissolve? (a) Aqueous \(\mathrm{NaOH}\) (b) Aqueous \(\mathrm{NaHCO}_{3}\) (c) Aqueous \(\mathrm{Na}_{2} \mathrm{CO}_{3}\)
See all solutions

Recommended explanations on Chemistry Textbooks

Ionic and Molecular Compounds

Read Explanation

Chemistry Branches

Read Explanation

The Earths Atmosphere

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.

Sign-up for free