Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Chemistry

How will you convert ethanal into the following compound?

But-2-enal

Write structural formulas and names of four possible aldol condensation products from propanal and butanal. In each case, indicate which aldehyde acts as nucleophile and which as electrophile.

How will you bring about the following conversion in not more than two steps?

Ethanol to 3-Hydroxybutanal

How will you bring about the following conversion in not more than two steps?

Benzaldehyde to 3-Phenylpropan-1-ol

Describe the following:

Cross aldol condensation

Complete the synthesis by giving missing starting material, reagent or product.

\[\begin{array}{cc}
\ce{C6H5CHO}\phantom{............}\\
\phantom{........}\ce{+\phantom{......}\ce{->[dil.NaOH][\Delta]}}\phantom{...}\\
\ce{CH3CH2CHO}\phantom{............}
\end{array}\]

Give the structure of the product you would expect when the following alcohol reacts with HCl–ZnCl₂.

Butan-1-ol

Give two reactions that show the acidic nature of phenol.

Explain how does the −OH group attached to a carbon of benzene ring activate it towards electrophilic substitution?

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.