CBSE 2026 · Region 2 · Set 1 · Q31 · 5 marks
(a)How will you convert the following : $\displaystyle 3$ + $\displaystyle 2$(i)Propanone to Propene(ii)Benzoic acid to Benzaldehyde(iii)Benzene to m-Nitroacetophenone(b)(i)Arrange the following compounds in increasing order of their reactivity towards HCN :
(ii)Identify the compounds, which would undergo Aldol condensation : $\displaystyle \mathrm{HCHO}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}, \mathrm{CH}_{3} \mathrm{CHO}$,(a)Give chemical tests to distinguish between the following pairs of compounds : $\displaystyle 3$ + $\displaystyle 2$(i)Acetophenone and Benzophenone(ii)Propanal and Propanone(iii)Pentan-$\displaystyle 2$-one and Pentan-$\displaystyle 3$-one(b)(i)Which of the following acids is stronger and why ? $\displaystyle \mathrm{CH}_{2} \mathrm{FCOOH}, \mathrm{CH}_{3} \mathrm{COOH}$(ii)Arrange the following compounds in the increasing order of their boiling points : $\displaystyle \mathrm{CH}_{3} \mathrm{OCH}_{3}, \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}, \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}, \mathrm{CH}_{3} \mathrm{CHO}$
(a)
How will you convert the following : $\displaystyle 3$ + $\displaystyle 2$
(i)
Propanone to Propene
(ii)
Benzoic acid to Benzaldehyde
(iii)
Benzene to m-Nitroacetophenone
(b)(i)
Arrange the following compounds in increasing order of their reactivity towards HCN :
(ii)
Identify the compounds, which would undergo Aldol condensation : $\displaystyle \mathrm{HCHO}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}, \mathrm{CH}_{3} \mathrm{CHO}$,
(a)
Give chemical tests to distinguish between the following pairs of compounds : $\displaystyle 3$ + $\displaystyle 2$
(i)
Acetophenone and Benzophenone
(ii)
Propanal and Propanone
(iii)
Pentan-$\displaystyle 2$-one and Pentan-$\displaystyle 3$-one
(b)(i)
Which of the following acids is stronger and why ? $\displaystyle \mathrm{CH}_{2} \mathrm{FCOOH}, \mathrm{CH}_{3} \mathrm{COOH}$
(ii)
Arrange the following compounds in the increasing order of their boiling points : $\displaystyle \mathrm{CH}_{3} \mathrm{OCH}_{3}, \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}, \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}, \mathrm{CH}_{3} \mathrm{CHO}$
Marking-scheme solution
(A)
.
(b)
(a) (i)
(ii)
(iii) (i)
(ii)
$\displaystyle 31$(B).
(i)
Acetophenone on heating with NaOH and I2, gives yellow precipitate of
iodoform whereas benzophenone does not give iodoform test.
(ii)
Propanal reduces Tollens’ reagent to silver whereas propanone does not.
(iii)
Pentan-$\displaystyle 2$-one on heating with NaOH and I2, gives yellow precipitate of
iodoform whereas Pentan-$\displaystyle 3$-one does not.
(i)
FCH2COOH is a stronger acid than CH3COOH.
Due to – I effect of F atom
(ii)
CH3CH2CH3 < CH3OCH3 < CH3CHO < CH3CH2OH
Aldehydes, Ketones and Carboxylic AcidsChemical Reactions of Aldehydes, Ketones and Carboxylic AcidsApplylong_answerhard
Practice Aldehydes, Ketones and Carboxylic Acids →All Aldehydes, Ketones and Carboxylic Acids questions
More from Aldehydes, Ketones and Carboxylic Acids
- The acid formed when propyl magnesium bromide is treated with CO 2 followed by acid hydrolysis is:2025 · asked 3×
- (i) Identify A, B and C in the following reactions: (ii) Give reasons for the following: (I) Carboxylic acids…2025 · asked 3×
- Give chemical tests to distinguish between the following pairs of compounds: (i) Phenol and Benzoic acid (ii)…2024 · asked 3×
- (i) Write the major product(s) in the following reactions: (2) (3) (ii) Give simple chemical tests to…2024 · asked 3×
- Explain the following reactions and write chemical equation involved: Wolff-Kishner reduction Etard reaction…2025 · asked 3×
- Assertion: Benzoic acid does not undergo Friedel - Crafts reaction. Reason (R): Carboxyl group is…2024 · asked 3×
- (i) Write the product(s) when: (I) One mol of ethanal is treated with 1 mol of CH 3 OH in the presence of dry…2026 · asked 3×
- The carbon - oxygen double bond is polarised in aldehydes and ketones due to higher electronegativity of…2023 · asked 3×
CBSE Class 12 Chemistry past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.