List of top Chemistry Questions on Aldehydes, Ketones and Carboxylic Acids asked in CBSE CLASS XII

An organic compound with the molecular formula \(C_8H_8O\) forms 2,4-DNP derivative, reduces Tollens’ reagent and undergoes Cannizzaro reaction. On vigorous oxidation it gives Benzene-1,2-dicarboxylic acid. Identify the compound and write the reactions of compound with 2,4-DNP and when it undergoes Cannizzaro reaction.

How do you convert Acetophenone to Benzoic acid ?

Write the product(s) when : (I) One mol of ethanal is treated with 1 mol of \(CH_3OH\) in the presence of dry HCl gas. (II) Benzaldehyde is treated with conc. NaOH. (III) Ethanoic acid is heated in the presence of \(P_2O_5\).

Assertion (A) : All aliphatic aldehydes give a positive Fehling’s test. Reason (R) : Aliphatic aldehydes are reduced by Fehling’s reagent.

Draw the structure of 'X' in the following reaction:
(a primary alcohol / suitable substrate) + CrO₃ → 'X'

Draw the structure of 'X' in the following reaction: a compound is treated with CrO₃ to give 'X'.

Show how each of the following compounds can be converted to benzoic acid: (I) Acetophenone; (II) Ethyl benzene.

Aspirin is obtained by acetylation of

Benzoic acid to Benzene

Draw the structure of 'X' in the following reaction:

Write the name of the reagent to convert Ethanenitrile to Ethanal.

Give a simple chemical test to distinguish between benzoic acid and ethyl benzoate.

Arrange the following in increasing order of their reactivity towards HCN:
Di-tert. butyl ketone, Acetaldehyde, Acetone

Draw structure of the 2, 4-dinitrophenyl hydrazone derivative of benzaldehyde.

Show how each of the following compounds can be converted to benzoic acid:
(I) Acetophenone
(II) Ethyl benzene

An organic compound (X) has the molecular formula \(C_5H_{10}O\). Draw structures for (X) if it:
(I) does not give Tollen's test but gives a positive iodoform test.
(II) does not give Tollen's test and iodoform test but undergoes Aldol condensation.
(III) undergoes Cannizzaro's reaction.

Nucleophilic addition of ammonia and its derivatives does not occur with carbonyl group in strongly acidic medium.

Alpha (\(\alpha\)) hydrogens of aldehydes and ketones are acidic in nature.

Arrange the following compounds in increasing order of their acidic strengths: \[ CH_3CH_2COOH,\quad CH_3CH(CH_3)COOH,\quad CH_3CH_2CH_2COOH,\quad BrCH_2CH_2COOH \]

Answer the following questions:
(i) Draw structure of the methyl hemiactetal of methanal.
(ii) There are two -NH$_2$ groups in semicarbazide. However, only one is involved in the formation of semicarbazones. Give reason.
(iii) How will you convert ethanol to 3-hydroxybutanal?

The acid formed when propyl magnesium bromide is treated with CO$_2$ followed by acid hydrolysis is:

Complete each synthesis by giving missing starting material, reagent, or products: (I) \(\text{CH}_3\text{CH}_3 + \text{KMnO}_4, \text{KOH} \longrightarrow \text{?}\)