What is meant by hydroboration-oxidation reaction?Illustrate it with an example.
What is meant by hydroboration-oxidation reaction?Illustrate it with an example.
Solution and Explanation
The addition of borane followed by oxidation is known as the hydroboration-oxidation reaction. For example,propan-1-ol is produced by the hydroboration-oxidation reaction of propene. In this reaction, propene reacts with diborane(BH3)2 to form trialkyl borane as an additional product.This additional product is oxidized to alcohol by hydrogen peroxide in the presence of aqueous sodium hydroxide
Top CBSE CLASS XII Chemistry Questions
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Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary amines.
(i) (CH3 )2CHNH2 (ii) CH3 (CH2 )2NH2 (iii) CH3NHCH(CH3 )2
(iv) (CH3 )3CNH2 (v) C6H5NHCH3 (vi) (CH3CH2 )2NCH3 (vii) m–BrC6H4NH2
Give one chemical test to distinguish between the following pairs of compounds.
(i) Methylamine and dimethylamine
(ii) Secondary and tertiary amines
(iii) Ethylamine and aniline
(iv) Aniline and benzylamine
(v) Aniline and N-methylanilineAccount for the following:
(i) pKb of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
(iv) Although amino group is o– and p– directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
(v) Aniline does not undergo Friedel-Crafts reaction.
(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines. (vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.
Top CBSE CLASS XII Alcohols, Phenols And Ethers Questions
Write the IUPAC names of the following compounds:
Write structures of the compounds whose IUPAC names are as follows:
(i)2-Methylbutan-2-ol
(ii)1-Phenylpropan-2-ol
(iii)3,5-Dimethylhexane -1,3,5-triol
(iv)2,3-Diethylphenol
(v)1- Ethoxypropane
(vi)2-Ethoxy-3-methylpentane
(vii)Cyclohexylmethanol
(viii)3-Cyclohexylpentan-3-ol
(ix)Cyclopent-3-en-1-ol
(x)3-Chloromethylpentan-1-ol.
Draw the structures of all isomeric alcohols of molecular formula C5H12O and give their IUPAC names. (ii)Classify the isomers of alcohols in question 11.3(i)as primary, secondary and tertiary alcohols.
Explain why propanol has a higher boiling point than that of the hydrocarbon, butane.
Alcohols are comparatively more soluble in water than hydrocarbons of comparable molecular masses. Explain this fact.
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