
Which reagent converts propene to propan - 1 - ol?
a) ${H}_{2}O, {H}_{2}S{O}_{4}$
b) ${B}_{2}{H}_{6}, {H}_{2}{O}_{2}, O{H}^{-}$
c) $Hg{(OAc)}_{2}, NaB{H}_{4}/{H}_{2}O$
d) Aq. $KOH$
Answer
126.9k+ views
Hint: Alkenes can be converted to alcohols by various methods. One such method to convert alkene to alcohol is through the hydroboration-oxidation reaction.
Complete step by step answer:
In hydroboration-oxidation reaction a two-step hydration reaction takes place that converts an alkene into an alcohol. The process results in the syn addition of a hydrogen and a hydroxyl group where the double bond had been present.
Thus, Propan-1-ol is produced by the hydroboration-oxidation reaction of propene.
In this reaction, propene reacts with diborane ${B}_{2}{H}_{6}$ to form trialkyl borane as an additional product. The product thus formed is oxidized to alcohol by hydrogen peroxide in the presence of aqueous sodium hydroxide.
$\underset { Propene }{ { C }_{ 3 }{ H }_{ 6 } } \quad +\quad \underset { Diborane }{ { B }_{ 2 }{ H }_{ 6 } } \quad \longrightarrow \quad { C }_{ 3 }{ H }_{ 7 }{ B }{ H }_{ 2 }$
${ C }_{ 3 }{ H }_{ 7 }{ B }{ H }_{ 2 }\quad +\quad \underset { Propene }{ { C }_{ 3 }{ H }_{ 6 } } \quad \longrightarrow \quad { { (C }_{ 3 }{ H }_{ 7 }) }_{ 2 }BH$
$\quad { { (C }_{ 3 }{ H }_{ 7 }) }_{ 2 }BH\quad +\quad \underset { Propene }{ { C }_{ 3 }{ H }_{ 6 } } \quad \longrightarrow \quad { ({ C }_{ 3 }{ H }_{ 7 }) }_{ 3 }B$
${ ({ C }_{ 3 }{ H }_{ 7 }) }_{ 3 }B\quad \xrightarrow [ { H }_{ 2 }O,\quad 3{ H }_{ 2 }{ O }_{ 2 } ]{ O{ H }^{ - } } \quad \underset { Propan-1-ol }{ 3{ C }_{ 3 }{ H }_{ 7 }OH } \quad +\quad B{ (OH) }_{ 3 }$
Therefore, The reagents that convert propene into propan - 1 - ol are ${B}_{2}{H}_{6}, {H}_{2}{O}_{2}, O{H}^{-}$.
Hence, option (b) is the correct answer.
Additional Information:
1. Diborane is a colorless, pyrophoric gas that has a repulsively sweet odor. Diborane and its variants are central organic synthesis reagents for hydroboration, whereby alkenes add across the B-H bonds to give trialkylboranes.
2. Hydrogen peroxide is a very pale blue liquid, slightly more viscous than water. Hydrogen peroxide is the simplest peroxide. Hydrogen peroxide can easily break down, or decompose, into water and oxygen by breaking up into two very reactive parts.
3. Diborane is used as a reducing agent. The compound readily reduces carboxylic acids to the corresponding alcohols, whereas ketones react only sluggishly.
4. Hydrogen peroxide is used as an oxidizer, bleaching agent, and antiseptic.
Note: Diborane is toxic in nature which is due to its irritant properties. Short-term exposure to diborane can cause a sensation of tightness of the chest, shortness of breath, cough, and wheezing.
Complete step by step answer:
In hydroboration-oxidation reaction a two-step hydration reaction takes place that converts an alkene into an alcohol. The process results in the syn addition of a hydrogen and a hydroxyl group where the double bond had been present.
Thus, Propan-1-ol is produced by the hydroboration-oxidation reaction of propene.
In this reaction, propene reacts with diborane ${B}_{2}{H}_{6}$ to form trialkyl borane as an additional product. The product thus formed is oxidized to alcohol by hydrogen peroxide in the presence of aqueous sodium hydroxide.
$\underset { Propene }{ { C }_{ 3 }{ H }_{ 6 } } \quad +\quad \underset { Diborane }{ { B }_{ 2 }{ H }_{ 6 } } \quad \longrightarrow \quad { C }_{ 3 }{ H }_{ 7 }{ B }{ H }_{ 2 }$
${ C }_{ 3 }{ H }_{ 7 }{ B }{ H }_{ 2 }\quad +\quad \underset { Propene }{ { C }_{ 3 }{ H }_{ 6 } } \quad \longrightarrow \quad { { (C }_{ 3 }{ H }_{ 7 }) }_{ 2 }BH$
$\quad { { (C }_{ 3 }{ H }_{ 7 }) }_{ 2 }BH\quad +\quad \underset { Propene }{ { C }_{ 3 }{ H }_{ 6 } } \quad \longrightarrow \quad { ({ C }_{ 3 }{ H }_{ 7 }) }_{ 3 }B$
${ ({ C }_{ 3 }{ H }_{ 7 }) }_{ 3 }B\quad \xrightarrow [ { H }_{ 2 }O,\quad 3{ H }_{ 2 }{ O }_{ 2 } ]{ O{ H }^{ - } } \quad \underset { Propan-1-ol }{ 3{ C }_{ 3 }{ H }_{ 7 }OH } \quad +\quad B{ (OH) }_{ 3 }$
Therefore, The reagents that convert propene into propan - 1 - ol are ${B}_{2}{H}_{6}, {H}_{2}{O}_{2}, O{H}^{-}$.
Hence, option (b) is the correct answer.
Additional Information:
1. Diborane is a colorless, pyrophoric gas that has a repulsively sweet odor. Diborane and its variants are central organic synthesis reagents for hydroboration, whereby alkenes add across the B-H bonds to give trialkylboranes.
2. Hydrogen peroxide is a very pale blue liquid, slightly more viscous than water. Hydrogen peroxide is the simplest peroxide. Hydrogen peroxide can easily break down, or decompose, into water and oxygen by breaking up into two very reactive parts.
3. Diborane is used as a reducing agent. The compound readily reduces carboxylic acids to the corresponding alcohols, whereas ketones react only sluggishly.
4. Hydrogen peroxide is used as an oxidizer, bleaching agent, and antiseptic.
Note: Diborane is toxic in nature which is due to its irritant properties. Short-term exposure to diborane can cause a sensation of tightness of the chest, shortness of breath, cough, and wheezing.
Recently Updated Pages
JEE Main 2025 - Session 2 Registration Open | Exam Dates, Answer Key, PDF

Difference Between Alcohol and Phenol

Classification of Drugs Based on Pharmacological Effect, Drug Action

JEE Main Mock Test Series Class 12 Chemistry for FREE

JEE Main 2023 (January 30th Shift 2) Maths Question Paper with Answer Key

JEE Main 2022 (July 25th Shift 2) Physics Question Paper with Answer Key

Trending doubts
JEE Main Login 2045: Step-by-Step Instructions and Details

JEE Main Exam Marking Scheme: Detailed Breakdown of Marks and Negative Marking

JEE Main 2023 January 24 Shift 2 Question Paper with Answer Keys & Solutions

JEE Main Participating Colleges 2024 - A Complete List of Top Colleges

Learn About Angle Of Deviation In Prism: JEE Main Physics 2025

Degree of Dissociation and Its Formula With Solved Example for JEE

Other Pages
NCERT Solutions for Class 12 Chemistry Chapter 8 Aldehydes Ketones and Carboxylic Acids

NCERT Solutions for Class 12 Chemistry Chapter 7 Alcohol Phenol and Ether

JEE Advanced 2025: Dates, Registration, Syllabus, Eligibility Criteria and More

NCERT Solutions for Class 12 Chemistry Chapter 5 Coordination Chemistry

NCERT Solutions for Class 12 Chemistry Chapter 4 The D and F Block Elements

The D and F Block Class 12 Notes: CBSE Chemistry Chapter 4
