Science (English Medium) Class 12 - CBSE Question Bank Solutions for Chemistry

Show how will you synthesize pentan-1-ol using a suitable alkyl halide.

Give the equation of the following reaction:

Oxidation of propan-1-ol with alkaline KMnO₄ solution.

Give the equation of the following reaction: 

Dilute HNO₃ with phenol.

Give the equation of the following reaction: 

Treating phenol with chloroform in the presence of aqueous NaOH.

Write the mechanism of acid-catalysed dehydration of ethanol to yield ethene.

Name the reagent used in the following reaction:

Oxidation of a primary alcohol to carboxylic acid.

Name the reagent used in the following reaction:

Oxidation of a primary alcohol to aldehyde.

Name the reagent used in the following reaction:

Benzyl alcohol to benzoic acid.

When 3-methylbutan-2-ol is treated with HBr, the following reaction takes place:

\[\begin{array}{cc}
\phantom{.......................}\ce{Br}\\
\phantom{......................}|\\
\ce{CH3 - CH - CH - CH3 ->[HBr] CH3 - C - CH2 - CH3}\\
\phantom{.}|\phantom{......}|\phantom{......................}|\phantom{........}\\
\phantom{}\ce{CH3}\phantom{...}\ce{OH}\phantom{...................}\ce{CH3}\phantom{.....}
\end{array}\]

Give a mechanism for this reaction.

(Hint: The secondary carbocation formed in step II rearranges to a more

stable tertiary carbocation by a hydride ion shift from 3rd carbon atom.)

Predict all the alkenes that would be formed by dehydrohalogenation of the following halide with sodium ethoxide in ethanol and identify the major alkene:

1-Bromo-1-methylcyclohexane

Predict all the alkenes that would be formed by dehydrohalogenation of the following halide with sodium ethoxide in ethanol and identify the major alkene:

2-Chloro-2-methylbutane

Predict all the alkenes that would be formed by dehydrohalogenation of the following halide with sodium ethoxide in ethanol and identify the major alkene:

2, 2, 3-Trimethyl-3-bromopentane

How will you bring about the following conversion?

But-1-ene to but-2-ene

Write the structure of the major organic product in the following reaction:

\[\ce{(CH3)3CBr + KOH ->[ethanol][heat]}\]

How the following conversion can be carried out?

1-Bromopropane to 2-bromopropane

How the following conversion can be carried out?

2-Chloropropane to 1-propanol

How the following conversion can be carried out?

2-Bromopropane to 1-bromopropane

What happens when PCl₅ is heated?

Write a balanced equation for the hydrolytic reaction of PCl₅ in heavy water.

Can PCl₅ act as an oxidising as well as a reducing agent? Justify.