NCERT Exemplar solutions for Chemistry [English] Class 12 chapter 12 - Aldehydes, Ketones and Carboxylic Acids [Latest edition]

Addition of water to alkynes occurs in acidic medium and in the presence of \[\ce{Hg^{2+}}\] ions as a catalyst. Which of the following products will be formed on addition of water to but-1-yne under these conditions.

Which of the following compounds is most reactive towards nucleophilic addition reactions?

The correct order of increasing acidic strength is ______.

Compound \[\begin{array}{cc}
\phantom{.....}\ce{O}\\
\phantom{.....}||\\
\ce{Ph - O - C - Ph}
\end{array}\] can be prepared by the reaction of ______.

The reagent which does not react with both, acetone and benzaldehyde.

Cannizaro’s reaction is not given by ______.

Which product is formed when the compound  is treated with concentrated aqueous \[\ce{KOH}\] solution?

\[\begin{array}{cc}
\ce{CH3 - C ≡ CH ->[40{%} H2SO4][1{%} HgSO4] A ->[Isomerisation] CH3 - C - CH3}\\
\phantom{........................................}||\\
\phantom{........................................}\ce{O}\\
\end{array}\]

Structure of ‘A’ and type of isomerism in the above reaction are respectively.

Compounds A and C in the following reaction are:

\[\ce{CH3CHO ->[(i) CH3MgBr][(ii) H2O] (A) ->[H2SO4, Δ] (B) ->[Hydroboration oxidation] (C)}\]

Which is the most suitable reagent for the following conversion?

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

Which of the following compounds will give butanone on oxidation with alkaline \[\ce{KMnO4}\] solution?

In Clemmensen Reduction carbonyl compound is treated with:

Which of the following compounds do not undergo aldol condensation?

(i) \[\ce{CH3 - CHO}\]

(ii)  

(iii)  \[\begin{array}{cc}
\phantom{}\ce{O}\\
\phantom{}||\\
\ce{CH3 - C - CH3}
\end{array}\]

(iv) \[\begin{array}{cc}
\phantom{}\ce{CH3}\\
|\phantom{...}\\
\ce{CH3 - C - CHO}\phantom{..}\\
|\phantom{...}\\
\phantom{}\ce{CH3}\\
\end{array}\]

Treatment of compound \[\begin{array}{cc}
\phantom{.....}\ce{O}\\
\phantom{.....}||\\
\ce{Ph - O - C - Ph}
\end{array}\] with \[\ce{NaOH}\] solution yields

(i) Phenol

(ii) Sodium phenoxide

(iii) Sodium benzoate

(iv) Benzophenone

Which of the following conversions can be carried out by Clemmensen Reduction?

(i) Benzaldehyde into benzyl alcohol

(ii) Cyclohexanone into cyclohexane

(iii) Benzoyl chloride into benzaldehyde

(iv) Benzophenone into diphenyl methane

Through which of the following reactions number of carbon atoms can be increased in the chain?

(i) Grignard reaction

(ii) Cannizaro’s reaction

(iii) Aldol condensation

(iv) HVZ reaction

Benzophenone can be obtained by:

(i) Benzoyl chloride + Benzene + \[\ce{AlCl3}\]

(ii) Benzoyl chloride + Diphenyl cadmium

(iii) Benzoyl chloride + Phenyl magnesium chloride

(iv) Benzene + Carbon monoxide + \[\ce{ZnCl2}\]

Which of the following is the correct representation for intermediate of nucleophilic addition reaction to the given carbonyl compound (A):

(i)  

(ii)  

(iii)  

(iv) 

Why is there a large difference in the boiling points of butanal and butan-1-ol?

Write a test to differentiate between pentan-2-one and pentan-3-one.

Give the IUPAC names of the following compounds.

Give the IUPAC names of the following compounds.

Give the IUPAC names of the following compounds.

\[\begin{array}{cc}
\ce{CH3 - CH2 - C - CH2 - CHO}\\
||\phantom{.}\\
\ce{O}\phantom{.}
\end{array}\]

Give the IUPAC names of the following compounds.

 \[\ce{CH3 - CH = CH - CHO}\]

Give the structure of the following compounds.

4-Nitropropiophenone

Give the structure of the following compounds.

2-Hydroxycyclopentanecarbaldehyde

Give the structure of the following compounds.

Phenyl acetaldehyde

Write IUPAC names of the following structures.

\[\begin{array}{cc}
\ce{CHO}\\
|\phantom{....}\\
\ce{CHO}\\
\end{array}\]

Write IUPAC names of the following structures.

Write IUPAC names of the following structures.

Benzaldehyde can be obtained from benzal chloride. Write reactions for obtaining benzalchloride and then benzaldehyde from it.

Name the electrophile produced in the reaction of benzene with benzoyl chloride in the presence of anhydrous \[\ce{AlCl3}\]. Name the reaction also.

Oxidation of ketones involves carbon-carbon bond cleavage. Name the products formed on oxidation of 2, 5-dimethylhexan-3-one.

Arrange the following in decreasing order of their acidic strength and give reason for your answer.

\[\ce{CH3CH2OH, CH3COOH, ClCH2COOH, FCH2COOH, C6H5CH2COOH}\]

What product will be formed on reaction of propanal with 2-methylpropanal in the presence of \[\ce{NaOH}\]? What products will be formed? Write the name of the reaction also.

Compound ‘A’ was prepared by oxidation of compound ‘B’ with alkaline \[\ce{KMnO4}\]. Compound ‘A’ on reduction with lithium aluminium hydride gets converted back to compound ‘B’. When compound ‘A’ is heated with compound B in the presence of \[\ce{H2SO4}\] it produces fruity smell of compound C to which family the compounds ‘A’, ‘B’ and ‘C’ belong to?

Arrange the following in decreasing order of their acidic strength. Give explanation for the arrangement.

\[\ce{C6H5COOH, FCH2COOH, NO2CH2COOH}\]

Alkenes   and carbonyl compounds , both contain a π bond but alkenes show electrophilic addition reactions whereas carbonyl compounds show nucleophilic addition reactions. Explain.

Carboxylic acids contain carbonyl group but do not show the nucleophilic addition reaction like aldehydes or ketones. Why?

Identify the compounds A, B and C in the following reaction.

\[\ce{CH3 - Br ->[Mg/ether] (A) ->[(i) CO][(ii) Water] (B) ->[CH3OH/H+][Δ] (C)}\]

Why are carboxylic acids more acidic than alcohols or phenols although all of them have hydrogen atom attached to a oxygen atom \[\ce{(-O-H)}\]?

Complete the following reaction sequence.

\[\begin{array}{cc}
\ce{O}\phantom{...............................................}\\
||\phantom{...............................................}\\
\ce{CH3 - C - CH3 ->[(i) CH3MgBr][H2O] (A) ->[Na metal][Ether] (B) ->[CH3 - Br] (C)}
\end{array}\]

Ethylbenzene is generally prepared by acetylation of benzene followed by reduction and not by direct alkylation. Think of a possible reason.

Can Gatterman-Koch reaction be considered similar to Friedel Craft’s acylation? Discuss.

Match the common names given in Column I with the IUPAC names given in Column II.

Match the acids given in Column I with their correct IUPAC names given in Column II.

Match the reactions given in Column I with the suitable reagents given in Column II.

Match the example given in Column I with the name of the reaction in Column II.

	Column I (Example)		Column II (Reaction)
(i)	\[\begin{array}{cc} \phantom{...}\ce{O}\phantom{..............................}\ce{O}\phantom{}\\ \phantom{...}||\phantom{..............................}||\phantom{}\\ \ce{CH3 - C - Cl + H2 ->[Pd - C/BasO4] CH3 - C - H} \end{array}\]	(a)	Friedel Crafts acylation
(ii)		(b)	HVZ reaction
(iii)		(c)	Aldol condensation
(iv)	\[\begin{array}{cc} \ce{R - CH2 - COOH ->[Br/Red P] R - CH - COOH}\\ \phantom{.....................}|\\ \phantom{.......................}\ce{Br} \end{array}\]	(d)	Cannizaro’s reaction
(v)	\[\ce{CH3 - CN ->[(i) SnCl2/HCl][(ii) H2O/H+] CH3CHO}\]	(e)	Rosenmund’s reductio
(vi)	\[\ce{2CH3CHO ->[NaOH] CH3 - CH = CHCHO}\]	(f)	Stephen’s reaction

Assertion: Formaldehyde is a planar molecule.

Reason: It contains sp² hybridised carbon atom.

Assertion: Compounds containing \[\ce{-CHO}\] group are easily oxidised to corresponding carboxylic acids.

Reason: Carboxylic acids can be reduced to alcohols by treatment with \[\ce{LiAlH4}\].

Assertion: The α-hydrogen atom in carbonyl compounds is less acidic.

Reason: The anion formed after the loss of α-hydrogen atom is resonance stabilised.

Assertion: Aromatic aldehydes and formaldehyde undergo Cannizaro reaction.

Reason: Aromatic aldehydes are almost as reactive as formaldehyde.

Assertion: Aldehydes and ketones, both react with Tollen’s reagent to form silver mirror.

Reason: Both, aldehydes and ketones contain a carbonyl group.

An alkene ‘A’ (Mol. formula \[\ce{C5H10}\]) on ozonolysis gives a mixture of two compounds ‘B’ and ‘C’. Compound ‘B’ gives positive Fehling’s test and also forms iodoform on treatment with \[\ce{I2}\] and \[\ce{NaOH}\]. Compound ‘C’ does not give Fehling’s test but forms iodoform. Identify the compounds A, B and C. Write the reaction for ozonolysis and formation of iodoform from B and C.

An aromatic compound ‘A’ (Molecular formula \[\ce{C8H8O}\]) gives positive 2, 4-DNP test. It gives a yellow precipitate of compound ‘B’ on treatment with iodine and sodium hydroxide solution. Compound ‘A’ does not give Tollen’s or Fehling’s test. On drastic oxidation with potassium permanganate it forms a carboxylic acid ‘C’ (Molecular formula \[\ce{C7H6O2}\]), which is also formed along with the yellow compound in the above reaction. Identify A, B and C and write all the reactions involved.

Write down functional isomers of a carbonyl compound with molecular formula \[\ce{C3H6O}\]. Which isomer will react faster with \[\ce{HCN}\] and why? Explain the mechanism of the reaction also. Will the reaction lead to the completion with the conversion of whole reactant into product at reaction conditions? If a strong acid is added to the reaction mixture what will be the effect on concentration of the product and why?

When liquid ‘A’ is treated with a freshly prepared ammoniacal silver nitrate solution, it gives bright silver mirror. The liquid forms a white crystalline solid on treatment with sodium hydrogensulphite. Liquid ‘B’ also forms a white crystalline solid with sodium hydrogensulphite but it does not give test with ammoniacal silver nitrate. Which of the two liquids is aldehyde? Write the chemical equations of these reactions also.