PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions for Chemistry

What is the role of graphite rod in the electrometallurgy of aluminium?

How does the presence of double bonds in rubber molecules influence their structure and reactivity?

Discuss the main purpose of vulcanisation of rubber.

Identify the monomer in the following polymeric structures.

An organic compound with the molecular formula C₉H₁₀O forms 2, 4-DNP derivative, reduces Tollens’ reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1, 2-benzenedicarboxylic acid. Identify the compound.

Describe the following:

Cannizzaro reaction

Ortho and para nitrophenols are more acidic than phenol. Draw the resonance structures of the corresponding phenoxide ions.

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:

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

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.)

Identify A, B, C, D, E, R and R¹ in the following:

How will you bring about the following conversion?

Bromomethane to propanone

How will you bring about the following conversion?

1-Chlorobutane to n-octane

Explain why Grignard reagents should be prepared under anhydrous conditions?