Reactions of Alcohol
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Questions and Answers

What is the result of treating alcohols with a strong acid?

  • The H is converted into a good leaving group
  • The O is converted into a good leaving group (correct)
  • The O is converted into a bad leaving group
  • The OH is removed from the α and β carbon atoms

    • What type of reaction is dehydration?

  • An oxidation reaction
  • A hydrolysis reaction
  • An elimination reaction (correct)
  • A substitution reaction

    • What is typically required for dehydration to occur?

  • A strong acid and a catalyst
  • A strong acid and a base
  • A weak acid and a base
  • A strong acid (correct)

    • Which alcohols dehydrate more easily?

    <p>More substituted alcohols</p> Signup and view all the answers

    What is the mechanism by which 2° and 3° alcohols react?

    <p>E1 mechanism</p> Signup and view all the answers

    What is the rule that follows the regioselectivity of dehydration?

    <p>Zaitsev's rule</p> Signup and view all the answers

    What is the product of dehydration when a mixture of constitutional isomers is possible?

    <p>The more substituted alkene</p> Signup and view all the answers

    What is the role of the amine base in dehydration?

    <p>It is present to stabilize the intermediate</p> Signup and view all the answers

    What is the primary factor in determining the alkene formed during dehydration?

    <p>Removal of the hydrogen from the beta-carbon having the fewest hydrogen substituents</p> Signup and view all the answers

    Why cannot 1° alcohols undergo dehydration by an E1 mechanism?

    <p>1° carbocations are highly unstable</p> Signup and view all the answers

    What is the role of POCl3 in the dehydration of alcohols?

    <p>It converts a poor leaving group into a good leaving group</p> Signup and view all the answers

    What is the advantage of using POCl3 and pyridine in dehydration reactions?

    <p>It allows for dehydration of secondary and tertiary alcohols at low temperatures</p> Signup and view all the answers

    What is necessary for a substitution reaction to occur with an alcohol?

    <p>The conversion of ¯OH into a good leaving group</p> Signup and view all the answers

    What is the result of reacting alcohols with HX (X = Cl, Br, I)?

    <p>The formation of alkyl halides</p> Signup and view all the answers

    What is the mechanism of dehydration of 1° alcohols?

    <p>E2 mechanism</p> Signup and view all the answers

    Why is Zaitsev's rule important in dehydration reactions?

    <p>It helps to predict the formation of alkenes</p> Signup and view all the answers

    What is the typical order of reactivity of alcohols with HX?

    <p>More substituted alcohols react more rapidly</p> Signup and view all the answers

    Why is ZnCl2 added to the reaction of 1o alcohols with HCl?

    <p>To complex with the O atom of the alcohol and facilitate the SN2 reaction</p> Signup and view all the answers

    What is the role of SOCl2 in the conversion of alcohols to alkyl halides?

    <p>It converts alcohols into alkyl chlorides</p> Signup and view all the answers

    What is the purpose of adding a Lewis acid catalyst in the reaction of 1o alcohols with HCl?

    <p>To make the O atom of the alcohol a better leaving group</p> Signup and view all the answers

    What is the trend in the reactivity of hydrogen halides?

    <p>The reactivity increases with increasing acidity</p> Signup and view all the answers

    What is the role of PBr3 in the conversion of alcohols to alkyl halides?

    <p>It converts alcohols into alkyl bromides</p> Signup and view all the answers

    What type of reaction occurs when alcohols react with HX?

    <p>SN2 reaction</p> Signup and view all the answers

    What is the stereochemistry of the products when the reaction occurs at a stereogenic center?

    <p>The stereochemistry can be predicted by knowing the mechanism of the reaction</p> Signup and view all the answers

    What is the purpose of SOCl2 and PBr3 in the conversion of alcohols to alkyl halides?

    <p>To convert ¯OH into a good leaving group in situ</p> Signup and view all the answers

    Why do more substituted alcohols react more rapidly with HX?

    <p>Because the reaction mechanism is affected by the structure of the R group</p> Signup and view all the answers

    What is the primary function of ZnCl2 in the reaction of 1o alcohols with HCl?

    <p>To form a good leaving group</p> Signup and view all the answers

    Why do PBr3 and SOCl2 convert alcohols into alkyl halides?

    <p>Because they convert ¯OH into a good leaving group and provide a nucleophile</p> Signup and view all the answers

    What is the relationship between the acidity of hydrogen halides and their reactivity?

    <p>The reactivity of hydrogen halides increases with increasing acidity</p> Signup and view all the answers

    What determines the stereochemistry of the products when the reaction occurs at a stereogenic center?

    <p>The mechanism of the reaction</p> Signup and view all the answers

    What is the role of the R group in the reaction of alcohols with HX?

    <p>It determines the mechanism of reaction</p> Signup and view all the answers

    Why is Cl¯ a poorer nucleophile than Br¯ or I¯?

    <p>Because it is a smaller atom</p> Signup and view all the answers

    What is the difference between the reaction of 1o alcohols with HCl and 2o or 3o alcohols with HX?

    <p>The reaction of 1o alcohols requires a catalyst, while 2o or 3o alcohols do not</p> Signup and view all the answers

    What is the function of the Lewis acid catalyst in the reaction of 1o alcohols with HCl?

    <p>To complex with the O atom of the alcohol</p> Signup and view all the answers

    Why do more substituted alcohols react more rapidly with HX?

    <p>Because they have a more stable carbocation intermediate</p> Signup and view all the answers

    What is the purpose of using thionyl chloride and phosphorus tribromide in the conversion of alcohols to alkyl halides?

    <p>To convert ¯OH into a good leaving group and provide a nucleophile</p> Signup and view all the answers

    More substituted alcohols react less rapidly with HX

    <p>False</p> Signup and view all the answers

    The reaction of 1o alcohols with HCl occurs without an additional Lewis acid catalyst

    <p>False</p> Signup and view all the answers

    SOCl2 converts alcohols into alkyl bromides

    <p>False</p> Signup and view all the answers

    The acidity of hydrogen halides decreases with increasing reactivity

    <p>False</p> Signup and view all the answers

    Complexation of ZnCl2 with the O atom of the alcohol makes a poor leaving group

    <p>False</p> Signup and view all the answers

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