CBSE Previous year questions (2019-2023)

Aldehydes, Ketones & Carboxylic acids

Multiple Choice Questions (1 mark)

1.	Which of the following is most reactive in nucleophilic addition reactions ? (a) HCHO (b) CH3CHO (c) CH3COCH3(d) CH3COC2H5	2023
2.	Which of the following does not give aldol condensation reaction ? (a) CH3–CHO           (b)  (c)(d) CH3COCH3	2023
3.	Which of the following does not give Cannizaroreaction ? (a) (CH3)3 C – CHO (b) (CH3)2 CH – CHO (c)(d) HCHO	2023
4.	Aldehydes and ketones react with hydroxylamine to form (a) hydrazones                (b) cyanohydrins (c) semicarbazones        (d) Oxime	2023
5.	The reagent that can be used to distinguish acetophenone and benzophenone is (a) 2, 4-dinitrophenyl hydrazine (b) aqueous NaHSO3 (c) Fehling solution                    (d) I2 and NaOH	2023
6.	Which of the following compounds will undergo self-condensation in the presence of dilute NaOHsolution ? (a) C6H5CHO                  (b) CH3CH2CHO (c) (CH3)3C – CHO         (d) H – CHO	2023
7.	The reactivities of the carbonyl compounds HCHO (I), CH3CHO (II) and CH3COCH3 (III) towards nucleophilic addition reaction decreases in the order : (a) III > II > I                    (b) I > II > III (c) II > III > I                     (d) I > III > II	2023
8.	A compound (A) with molecular formula C5H10O, forms a phehylhydrazone and gives negative Tollen’s and iodoform test. The compound on reduction gives n-pentane. The compound (A) is : (a) Pentan-3-one             (b) Pentanal (c) Pentanol                    (d) Pentan-2-one	2023
9.	Which of the following reagents would one choose to transform CH3COCl into acetone ? (a) (CH3)2Cd                   (b) CH3MgBr (c) CH3Cl                         (d) (CH3O)2Mg	2023
10.	This reaction is known as : (a) Aldol condensation    (b) Cross-Aldol condensation (c) Cannizzaro’s reaction(d) Friedel-Crafts reaction	2023
11.	The product formed in the reaction :	2023
12.	This reaction is known as : (a) Cannizzaro reaction               (b) Etard reaction (c) Rosenmund reduction            (d) Aldol condensation	2023
13.	Which of the following is an ‘Acetal’.?	2023
14.	Which one of the following has lowest pKavalue ?  (a) CH3 – COOH                        (b) O2N – CH2 – COOH  (c) Cl – CH2 – COOH                 (d) HCOOH	2023
15.	Acetyl chloride is treated with H2 in the presence of Pd-BaSO4. The product formed is : (a) CH3CH2OH                        (b) CH3CHO (c) CH3COOH                         (d) CH3COCH3	2023
16.	What would be the major product of the given reaction ? (a) Ethanal                                (b) Propanol (c) Ethanol                                (d) Propanal	2023 (c)
17.	Pentan-2-one and Pentan-3-one can be distinguished by : (a) Fehling’s test                        (b) Sodium bicarbonate test (c) Tollen’s test                          (d) Iodoform test	2023 (c)
18.	Clemmensen Reduction of aldelydes and ketonic carbonyl groups into methylene group is effected by the reagent : (a) H2, Pd                                   (b) LiAlH4 (c) Zn-Hg, conc. HCl                 (d) NH2-NH2, KOH	2023 (c)
19.	Which of the following methods is used to convert ketone into hydrocarbon ? (A) Aldol condensation            (B) Reimer-Tiemann reaction (C) Cannizzaro reaction           (D) Wolff-Kishner reduction	2020 (c)
20.	The IUPAC name for the formula             CH3              | CH3 – C = CH – COOH is (A) 2-Methylbut-2-enoic acid            (B) 3-Methylbut-3-enoic acid (C) 3-Methylbut-2-enoic acid            (D) 2-Methylbut-3-enoic acid	2020
21.	Iodoform test is not given by (A) Ethanol                                        (B) Ethanal (C) Pentan-2-one                               (D) Pentan-3-one	2020
22.	What is the correct IUPAC name of the given compound ? (A) 2,2-Dimethylbutanoic acid            (B) 2-Carboxyl-2-methylbutane (C) 2-Ethyl-2-methylpropanoic acid   (D) 3-Methylbutane carboxylic acid	2020
23.	Iodoform test is not given by (A) Hexan-2-one                                (B) Hexan-3-one (C) Ethanol                                        (D) Ethanal	2020
24.	Iodoform test is given by (A) Pentan-2-one                                (B) Ethanoic acid (C) Pentan-3-one                                (D) Methoxymethane	2020
	For following questions, two statements are given one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below. (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A). (c) Assertion (A) is true, but Reason (R) is false. (d) Assertion (A) is false, but Reason (R) is true.
1.	Assertion (A) : Acetic acid but not formic acid can be halogenated in presence of red P and Cl2. Reason (R) : Acetic acid is a weaker acid than formic acid.	2023
2.	Assertion (A) :Bromination of benzoic acid gives m-bromobenzoic acid. Reason (R) : Carboxyl group increases the electron density at the meta position.	2023
3.	Assertion (A) : The final product in Aldol condensation is always α,β - unsaturated carbonyl compound. Reason (R) : α,β -unsaturated carbonyl compounds are stabilised due to conjugation	2023
4.	Assertion (A) : All aldehydes do not take part in aldol condensation. Reason (R) : In aldol condensation, carbanion is generated by the abstraction of α-H atom by the base.	2020
5.	Assertion (A) : Reactivity of ketones is more than aldehydes. Reason (R) : The carbonyl carbon of ketones is less electrophilic as compared to aldehydes.	2020
6.	Assertion (A) : Acetic acid is stronger than formic acid. Reason (R) : In acetic acid, the electron releasing methyl group makes it difficult to break the O – H bond.	2020
7.	Assertion (A) : Reactivity of ketones is more than aldehydes. Reason (R) : The carbonyl carbon of ketones is less electrophilic as compared to aldehydes.	2020
8.	Assertion (A) : Benzoic acid does not undergo Friedal-Crafts reaction. Reason (R) : The carboxyl group is activating and undergo electrophilic substitution reaction.	2020
9.	Assertion (A) : Benzoic acid does not undergo Friedal-Crafts reaction. Reason (R) : The carboxyl group is activating and undergo electrophilic substitution reaction.	2020
10.	Assertion (A) : Oxidation of ketones is easier than aldehydes. Reason (R) : C-C bond of ketones is stronger than C-H bond of aldehydes.	2020
11.	Assertion (A) : Oxidation of ketones is easier than aldehydes. Reason (R) : C-C bond of ketones is stronger than C-H bond of aldehydes.	2020
12.	Assertion (A) : Benzaldehyde is less reactive than ethanal towards nucleophilic addition reactions. Reason (R) :Ethanal is more sterically hindered.	2020
	Very Short Answer type questions (1 marks)
1.	Draw the structure of semicarbazone of cyclopentanone. OR Draw the structure of product formed when propanal is treated with zinc  amalgam and concentrated hydrochloric acid.	2019
2.	α - hydrogen atoms of aldehydes and ketones are acidic in nature. Why?	2019 (V)
3.	Write the IUPAC name of the following compound :	2019
4.	Arrange the following in increasing order of their acidic character : Benzoic acid, Phenol, Cresol	2019
5.	CH3CHO is more reactive than CH3COCH3 towards reaction with HCN.Why ?	2019

 

   

 

Very Short Answer type questions (2 marks)

1.	Do the following conversions in not more than two steps :	2023
2.	Do the following conversions in not more than two steps : (a) CH3COOH to CH3COCH3 (b)	2023
3.	Write the chemical equation involved in the following reactions : (a) Reimer-Tiemann reaction (b) Acetylation of Salicylic acid	2023
4.	Give reasons for the following : (a) Carboxylic carbon is less electrophilic than Carbonyl carbon of aldehydes and ketones. (b) Propanal is more reactive than Propanone towards addition of HCN.	2023
5.	Give reasons : (a) Formic acid is a stronger acid than acetic acid. (b) Alpha (α)-Hydrogens of aldehydes and ketones are acidic.	2023
6.	(a) Write the products of the following reactions : OR (b) Do the following conversions in not more than two steps : (i) Toluene to Benzoic acid (ii) Benzaldehyde to 1-Phenylethanol	2023
7.	(a) Write the products of the following reactions : OR (b) Do the following conversions in not more than two steps : (i) Toluene to Benzoic acid (ii) Benzaldehyde to 1-Phenylethanol	2023
8.	Give reasons : (a) Oxidation of aldehydes is easier than that of ketones. (b) Carboxylic acid is a stronger acid than phenol.	2023
9.	(a) Why is pKa of ClCH2COOH lower than the pKa value of CH3COOH ? (b) Write the chemical equation for Hell-Volhard-Zelinsky reaction.	2023 (c)
10.	(a) Why is F CH2COOH a stronger acid than CH3COOH ? (b) Write the chemical equation for Wolff-Kishner reduction.	2023 (c)
11.	(a) Why is CH3CHFCH2COOH a stronger acid than CH2FCH2CH2COOH ? (b) Write chemical equation for Stephen’s reaction.	2023 (c)
12.	How will you convert ethanal into : (a) But-2-enal (b) Ethanol	2023 (c)
13.	How will you carry out the following conversions : (Any two) (i) Propanal to Propane (ii) Ethanal to But-2-enal (iii) Ethanoic acid to ethanamide	2022
14.	Predict the products formed when CH3CH2CHO reacts with the following reagents : (Any two) (i) PhMgBr and then H3O+ (ii) LiAlH4 (iii) HCN	2022
15.	Predict the products formed when CH3CHO reacts with the following reagents : (Any two) (i) CH3MgBr and then H3O+ (ii) Zn(Hg)/Conc. HCl (iii) Tollen’s reagent	2022
16.	Arrange the following compounds in the increasing order of their property indicated : (Any two) (i) Acetaldehyde, Benzaldehyde, Acetophenone, Acetone (Reactivity towards HCN) (ii) (CH3)2CHCOOH, CH3CH2CH(Br)COOH, CH3CH(Br)CH2COOH (Acidic strength) (iii) CH3CH2OH, CH3CHO, CH3COOH (Boiling point)	2022
17.	Write reasons for the following statements : (i) Benzoic acid does not undergo Friedel-Crafts reaction. (ii) Oxidation of aldehydes is easier than that of ketones.	2022
18.	Give reasons for the following statements : (Any two) (i) Benzaldehyde is less reactive than propanal in nucleophilic addition reactions. (ii) Carboxylic acids do not give reactions of carbonyl group. (iii) 4-nitrobenzoic acid is a stronger acid than benzoic acid.	2022
19.	(i) (CH3)3C CHO does not undergo aldol condensation. Why ? (ii) Distinguish between Acetophenone and Benzophenone with the help of a chemical test.	2022
20.	(a) Arrange the following compounds in the increasing order of their acidic strength : Cl CH2 COOH, Cl2 CH COOH, CCl3 COOH  (b) Write the IUPAC name of the given compound : CH3COCH2COCH3	2022 (c)
21.	(a) Arrange the following compounds in the increasing order of theiracidic character : FCH2COOH, NO2CH2COOH, C6H5COOH (b) Write the IUPAC name of the given compound : CH3 CH2CH2CHO	2022 (c)
22.	a) Arrange the following compounds in the increasing order of their boiling points : CH3COCH3, CH3CH2OH, CH3COOH (b) Write the IUPAC name of the given compound :	2022 (c)
23.	Write the chemical reaction involved in the following reactions: (a)    Clemmensen reduction (b)   Rosenmund reaction	2022 (c)
24.	A and B are two functional isomers of compound C3H6O. On heating with NaOH and I2,  isomer A forms yellow precipitate of iodoforms, whereas isomer B does not form any precipitate. Write the structures of A and B.	2020 (c)
25.	What happens when (a) Butanone is treated with methylmagnesium bromide and then hydrolysed,and (b) Sodium benzoate is heated with soda lime ?	2020
26.	What happens when (a) Acetone is treated with Zn(Hg) / Conc. HCl, and (b) Ethanal is treated with methylmagnesium bromide and thenhydrolysed ?	2020
27.	How are the following conversions carried out ? (a) CH3CN to CH3COCH3 (b) Benzoic acid to Benzoyl chloride	2019 (V)
28.	Write structures of compounds A and B in each of the following reactions :	2019
29.	Write structures of main compounds A and B in each of the following reactions :	2019

 

Short Answer type questions (3 marks)

1.	(a) Explain why : (i) Carboxyl group in benzoic acid is meta directing. (ii) Sodium bisulphite is used for the purification of aldehydes and ketones. (iii) Carboxylic acids do not give characteristic reactions of carbonyl group. OR An organic compound ‘A’, having the molecular C3H8O on treatment with Cu at 573 K, gives ‘B’.’B’ does not reduces Fehling’s solution but gives a yellow precipitate of compound ‘C’ with I2/NaOH. Deduce the structure of A, B & C.	2023
2.	How do you convert the following : (Any three) (a) Phenol to 2-Hydroxybenzaldehyde (b) Anisole to 2-Methoxyacetophenone (c) Propene to Propan-2-ol (d) Ethanol to Ethanal	2023
3.	(a) Explain why : (i) Carboxyl group in benzoic acid is meta directing. (ii) Sodium bisulphite is used for the purification of aldehydes and ketones. (iii) Carboxylic acids do not give characteristic reactions of carbonyl group. OR (b) Give chemical equation for the following reactions : (i) Propanone is treated with dil. Ba(OH)2. (ii) Acetophenone is treated with Zn(Hg)/Conc. HCl. (iii) Benzoyl chloride is hydrogenated in presence of Pd-BaSO4.	2023
4.	(a) Write the major products in the following : OR (b) (i) Oxidation of propanal is easier than propanone. Why ? (ii) How can you distinguish between Acetophenone andBenzophenone ? (iii) Draw the structure of the following derivative : 2,4-Dinitrophenylhydrazone of Propanone	2022
5.	(a) Write the equation involved in the following reactions : (i) Rosenmund reduction (ii) Etard reaction (iii) Stephen reaction OR (b) (i) Which acid of each pair would you expect to be stronger ? Give reason. (I) CH3COOH or F CH2 COOH (II) or CH3 COOH (ii) Distinguish between Pentan-2-one and Pentan-3-one.	2022
6.	(a) Write the equations involved in the following reactions : (i) Cannizzaro reaction (ii) Aldol condensation (iii) Hell-Volhard-Zelinsky reaction OR (b) (i) Which acid of each pair would you expect to be stronger ? Give reason. (I) F CH2 COOH or Cl CH2 COOH   (II)   (ii) Distinguish between Propanal and Propanone.	2022
7.	(a) Predict the products in the following reactions : OR (b) Arrange the following compounds in increasing order of their property as indicated:	2022
8.	(a) Write the major products in the following : OR (b) (i) Oxidation of propanal is easier than propanone. Why ? (ii) How can you distinguish between Acetophenone and Benzophenone ? (iii) Draw the structure of the following derivative : 2,4-Dinitrophenylhydrazone of Propanone	2022
9.		2022
10.	(a) Give reasons for the following : (i) In semicarbazide, there are two NH2 groups, but only one is involved in the formation of semicarbazones. (ii) Carboxylic acid is a stronger acid than phenol. (iii) α-hydrogens of aldehydes and ketones are acidic in nature. OR (b) An organic compound (A) with molecular formula C5H10O does not reduce Tollen’s reagent, but forms an addition compound with NaHSO3 and gives positive iodoform test on heating with NaOH in the presence of I2. On vigorous oxidation, it gives ethanoic and propanoic acid. Write (i) the possible structure of the compound. (ii) the IUPAC name of the compound. (iii) the reaction of (A) with NaHSO3.	2022
11.	(a) Write the reaction of ethanal with (i)                 LiAlH4 (ii)               Dil. NaOH (iii)             HCN OR (b) How will you convert the following: (i) Ethanoic acid to 2-chloroethanoic acid (ii) Propanone to t-butyl alcohol (iii) CH3CH=CHCH2CN to CH3CH=CHCH2CHO	2022 (c)
12.	(a) Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions: Ethanal. Propanal, Propanone. Butanone. (b) Why does Benzaldehyde not undergo aldol condensation? (c) Write a simple chemical test to distinguish between Pentan-2-one and Pentan-3-one.	2022 (c)
13.	Write the structures of A and B in the following :	2020
14.	Write the products formed when (CH3)3 C – CHO reacts with the following reagents :  (i) CH3COCH3 in the presence of dilute NaOH (ii) HCN (iii) Conc. NaOH	2020
15.	Write the product(s) of the following reactions :
16.	An organic compound (A) which has characteristic odour, on treatment with NaOH forms two compounds, (B) and (C). Compound (B) has molecular formula C7H8O, which on oxidation with CrO3 gives back compound (A). Compound (C) is the sodium salt of the acid. Compound (C) when heated with soda lime yields an aromatic hydrocarbon (D). Identify the structures A, B, C and D.	2019 (V)
17.	Complete the following reactions : OR Write chemical equations for the following reactions : (i) Propanone is treated with dilute Ba(OH)2. (ii) Acetophenone is treated with Zn(Hg)/Conc. HCl (iii) Benzoyl chloride is hydrogenated in presence of Pd/BaSO4.	2019
18.	(a) Give reasons : (i) Benzoic acid is a stronger acid than acetic acid. (ii) Methanal is more reactive towards nucleophilic addition reaction than ethanal. (b) Give a simple chemical test to distinguish between propanal and propanone.	2019

 

Case based questions. (4 marks)

The following questions are case based questions. Read the passage carefully and answer the questions that follow :

1.

The carbon – oxygen double bond is polarised in aldehydes and ketones due to higher electronegativity of oxygen relative to carbon. Therefore they undergo nucleophilic addition reactions with a number of nucleophiles such as HCN, NaHSO3, alcohols, ammonia derivatives and Grignard reagents. Aldehydes are easily oxidised by mild oxidising agents as compared to ketones. The carbonyl group of carboxylic acid does not give reactions of aldehydes and ketones. Carboxylic acids are considerably more acidic than alcohols and most of simple phenols. Answer the following :   (a) Write the name of the product when an aldehyde reacts with excess alcohol in presence of dry HCl. (b) Why carboxylic acid is a stronger acid than phenol ? (i)  Arrange the following compounds in increasing order of their reactivity towards CH3MgBr: (ii) Write a chemical test to distinguish between propanal and propanone. OR I Write the main product in the following :

2023

 

 

 

Long Answer type questions (5 marks)

1.	(i) Carry out the following conversions : (1) Ethanal to But-2-en-1-al (2) Propanoic acid to 2-chloropropanoic acid (ii) An alkene with molecular formula C5H10 on ozonolysis gives a mixture of two compounds ‘B’ and ‘C’. Compound ‘B’ gives positive Fehling test and also reacts with iodine and NaOH solution. Compound ‘C’ does not give Fehling’s solution test but forms iodoform. Identify the compounds ‘A’, ‘B’ & ‘C’. OR (b) (i) Distinguish with a suitable chemical test : (1) CH3COCH2CH3 and CH3CH2CH2CHO (2) Ethanal and Ethanoic acid      (ii) Write the structure of oxime of acetone. (i)                             Identify A to D.	2023
2.	(i) Carry out the following conversions : (1) Ethanal to But-2-en-1-al (2) Propanoic acid to 2-chloropropanoic acid (ii) An alkene with molecular formula C5H10 on ozonolysis gives a mixture of two compounds ‘B’ and ‘C’. Compound ‘B’ gives positive Fehling test and also reacts with iodine and NaOH solution. Compound ‘C’ does not give Fehling’s solution test but forms iodoform. Identify the compounds ‘A’, ‘B’ & ‘C’. OR (b) (i) Distinguish with a suitable chemical test : (1) CH3COCH2CH3 and CH3CH2CH2CHO (2) Ethanal and Ethanoic acid (ii) Write the structure of oxime of acetone. (ii)                           Identify A to D.	2023
3.	(a) (i) An organic compound (X) having molecular formula C5H10O can show various properties depending on its structures. Draw each of the structures if it (1) gives positive iodoform test. (2) shows cannizzaro’s reaction (3) reducesTollen’s reagent and has a chiral carbon. (ii) Write the reaction involved in the following : (1) Wolff-Kishner reduction (2) Hell-Volhard-Zelinsky reaction OR (b) (i) How can you convert each of the following compounds to Benzoic acid ? (1) Acetophenone (2) Ethylbenzene (3) Bromobenzene (ii) Arrange the following compounds in increasing order of their property as indicated : (1) O2N CH2 COOH, F CH2 COOH, CN CH2COOH (Acidic character) (2) Ethanal, Propanal, Butanone, Propanone (Reactivity in nucleophilic addition reactions)	2023
4.	(a) Draw structure of the 2,4-dinitrophenylhydrazone of benzaldehyde. (b) Which acid of the following pair is a stronger acid ? (c) Write the chemical equation involved in Rosenmund reduction. (d) Why are α-hydrogen atoms of aldehydes and ketones acidic in nature ? I Write a chemical test to distinguish between Benzaldehyde andBenzoic acid.	2023
5.	(a) (i) Write the reaction involved in Cannizaro’s reaction.  (ii) Why are the boiling point of aldehydes and ketones lower thanthat of corresponding carboxylic acids ?  (iii) An organic compound ‘A’ with molecular formula C5H8O2 is reduced to n-pentane with hydrazine followed by heating with NaOH and Glycol. ‘A’ forms a dioxime with hydroxylamine and gives a positive Iodoform and Tollen’s test. Identify ‘A’ and give its reaction for Iodoform and Tollen’s test. OR (b) (i) Give a chemical test to distinguish between ethanal acid and ethanoic acid.  (ii) Why is the α-hydrogens of aldehydes and ketones are acidic in nature ?  (iii) An organic compound ‘A’ with molecular formula C4H8O2 undergoes acid hydrolysis to form two compounds ‘B’ and ‘C’. Oxidation of ‘C’ with acidified potassium permanganate also produces ‘B’. Sodium salt of ‘B’ on heating with soda lime gives methane.  (1) Identify ‘A’, ‘B’ and ‘C’.  (2) Out of ‘B’ and ‘C’, which will have higher boiling point ? Give reason.	2023
6.	(a) ‘A’ and ‘B’ are the two functional isomers of compound C3H6O. On heating with I2 and NaOH, isomer ‘B’ forms yellow precipitate of iodoform whereas isomer ‘A’ does not form any precipitate. Identify ‘A’ and ‘B’. (b) Give reasons for the following : (i) Carboxylic acid does not give reactions of carbonyl group.  (ii) Propanone is less reactive towards nucleophilic addition reaction as compared to propanal. I Write a simple chemical test to distinguish between benzoic acid and phenol.	2023
7.	(a) Compound A undergoes Rosenmund reduction to give compound B with molecular formula C7H6O. Compound B does not give Fehling s test but reacts with conc. NaOH to give C and D.  Identify A, B, C and D and write all the reactions involved.  Write one chemical test to distinguish between compound B and propanone. OR (b) Compound A with molecular formula (C2H6O) on oxidation by PCC gives compound B, which on treatment with dilute alkali forms compound C which is a –hydroxy aldehyde. B on oxidation by potassium permanganate forms C. Identify A, B, C and D and write all the chemical equations involved.	2023
8.	(a) (i) Write the products formed when Methanal reacts with the following :  (1) Concentrated NaOH  (2) Semicarbazide/weak acid  (3) CH3MgBr/H2O (ii) Write the reaction involved in  (1) Hell-Volhard-Zelinsky reaction, and  (2) Decarboxylation reaction OR (b) (i) How will you convert the following ?  (1) Toluene to Benzaldehyde  (2) Acetyl chloride to Ethanol  (ii) Write a simple chemical test to distinguish between the following pairs of compounds : (1) Pentan-2-one and Pentan-3-one (2) Benzoic acid and Benzaldehyde IChloroacetic acid is more acidic than acetic acid. Why ?	2023
9.	Read the passage given below and answer the questions that follow : Aldehydes differ from ketones in their oxidation reactions. Aldehydes are easily oxidised to carboxylic acids on treatment with common oxidising agents like nitric acid, KMnO4, K2Cr2O7, etc. Even Mild oxidizing agents mainly Tollen’s reagent and Fehling solution also oxidise aldehydes. Ketonesare generally oxidised under vigorous conditions.Aldehydes and ketones undergo nucleophilc addition reactionsonto the carbonyl group with a number of nucleophiles such as HCN, NaHSO3, alcohols, ammonia derivatives and Grignardreagents. The α-hydrogens of aldehydes and ketones are acidicdue to which they undergo Aldol condensation. (i) Why is the oxidation of Aldehydes easier than Ketones ? (ii) Arrange the following compounds in the increasing order of their reactivity towards nucleophilic addition reaction : Ethanal, Acetone, Propanal, Acetophenone (iii) Write a simple chemical test to distinguish between Acetone and Ethanal. (iv) (a) Write the major product in the following reactions : OR (b) How will you bring about the following conversions ? (I) Benzoic acid to Benzaldehyde (II) Propan-2-ol to Propanone	2022
10.	Read the following passage and answer the questions that follow : A class of organic molecules which contain a carbon atom connected to an oxygen atom by a double bond is called Aldehydes and Ketones. It is called as carbonyl group. Aldehydes are prepared by the oxidation of alcohols. Formaldehyde is sold in an aqueous solution called formalin. Propanone, a simplest ketone is commercially prepared by fermenting corn or by oxidation of propan-2-ol. Carboxylic acids also have carbonyl carbon. They can be prepared by the oxidation of alcohols and aldehydes. Formic acid was first isolated by the distillation of red ants. It is partially responsible for the pain and irritation of ant and wasp stings. Aldehydes undergo many nucleophilic addition reactions. They can be reduced to primary alcohols. The aldehydes with α-hydrogen undergo aldol condensation and the aldehydes without –hydrogen undergoCannizzaro reaction. Ketones are highly reactive, although less so than aldehydes. Ketones are obtained by oxidation of secondary alcohols. Ketones possessing α-hydrogens also undergo aldol condensation. Carboxylic acids occur widely in nature and are used in the production of plastics, esters, etc. Aspirin is prepared from acetic acid. Similar to aldehydes and ketones, carboxylic acids can be halogenated at the –carbon by reacting with a halogen in presence of phosphorus. (a) Which of the following compounds would undergo aldol condensation ? Methanal, Benzaldehyde, Ethanal (b) Write the chemical test to distinguish between propanal and propanone. (c) Write the reagent required in the following reaction : (d) (i) An alcohol ‘A’ (C3H8O) on oxidation gives compound ‘B’. ‘B’ gives negative Tollen’s test and reacts with hydrazine to give compound ‘C’. ‘B’ reacts with NaOH and I2 to give yellow precipitate of ‘D’. Identify ‘A’, ‘B’, ‘C’ & ‘D’. OR (ii) Write the chemical reactions for the following : (I) Clemmensen reduction (II) HVZ reaction	2022
11.	(a) Draw the structures of the following derivatives : (i) 2,4-DNP of benzaldehyde (ii) Propanone oxime (b) Complete the following synthesis : (c) Carboxylic acid is a stronger acid than phenol. Justify. OR (a) An organic compound ‘A’ with molecular formula C4H8O2 was hydrolysed with dil. H2SO4 to give a carboxylic acid ‘B’ and an alcohol ‘C’. ‘C’ on dehydration gives thane and ‘C’ also on oxidation gives back ‘B’. Identify ‘A’, ‘B’ and ‘C’ and write the chemical equations for the reactions involved. (b) How will you convert ethanal into the following compounds ? (i) Ethanol (ii) Ethane	2020
12.	(a) An organic compound ‘A’ having molecular formula C5H10O gives negative Tollens’ test, forms n-pentane on Clemmensen reduction but doesn’t give iodoform test. Identify ‘A’ and give all the reactions involved. (b) Carry out the following conversions : (i) Propanoic acid to 2-Bromopropanoic acid (ii) Benzoyl chloride to benzaldehyde (c) How will you distinguish between benzaldehyde and acetaldehyde ? OR (a) Complete the following sequence of reactions : (i) Identify (A) to (D).  (ii) Give the IUPAC name of (A). (b) How can you distinguish between : (i) Ethanol and Propanone, and (ii) Benzoic acid and Phenol ?	2020
13.	(a) An organic compound (A) having molecular formula C4H8O gives orange red precipitate with 2, 4-DNP reagent. It does not reduce Tollens’ reagent but gives yellow precipitate of iodoform on heating with NaOH and I2. Compound (A) on reduction with NaBH4 gives compound (B) which undergoes dehydration reaction on heating with conc. H2SO4 to form compound (C). Compound (C) on Ozonolysis gives two molecules of ethanal. Identify (A), (B) and (C) and write their structures. Write the reactions of compound (A) with (i) NaOH/I2 and (ii) NaBH4. (b) Give reasons : (i) Oxidation of propanal is easier than propanone. (ii) α-hydrogen of aldehydes and ketones is acidic in nature. OR (a) Draw structures of the following derivatives : (i) Cyanohydrin of cyclobutanone (ii) Hemiacetal of ethanal (b) Write the major product(s) in the following : (c) How can you distinguish between propanal and propanone ?	2020
14.	(a) Write the products formed when benzaldehyde reacts with the following reagents : (i) CH3CHO in presence of dilute NaOH (ii)  (iii) Conc. NaOH (b) Distinguish between following : (i) CH3 – CH = CH – CO – CH3 and CH3 – CH2 – CO – CH = CH2 (ii) Benzaldehyde and Benzoic acid. OR (a) Write the final products in the following : (b) Arrange the following in the increasing order of their reactivity towards  nucleophilic addition reaction : (c) Draw the structure of 2, 4 DNP derivative of acetaldehyde.	2020
15.		2020
16.		2019
17.	(c) Why is alpha α – hydrogen of carbonyl compounds acidic in nature ? OR (a) Write the main product formed when propanal reacts with the following reagents : (i) 2 moles of CH3OH in presence of dry HCl (ii) Dilute NaOH (iii) H2N – NH2 followed by heating with KOH in ethylene glycol (b) Arrange the following compounds in increasing order of their property as indicated : (i) F – CH2COOH, O2N – CH2COOH, CH3COOH, HCOOH — acid character (ii) Acetone, Acetaldehyde, Benzaldehyde, Acetophenone — reactivity towards addition of HCN	2019
18.	(a) Carry out the following conversions : (i) P-nitrotoluene to 2-bromobenzoic acid (ii) Propanoic acid to acetic acid (b) An alkene with molecular formula C5H10 on ozonolysis gives a mixture of two compounds, B and C. Compound B gives positive Fehling test and also reacts with iodine and NaOH solution. Compound C does not give Fehling solution test but forms iodoform. Identify the compounds A, B and C. OR (a) Carry out the following conversions : (i) Benzoic acid to aniline (ii) Bromomethane to ethanol (b) Write the structure of major product(s) in the following :	2019
19.	(a) Give IUPAC name of CH3 – CH = CH – CHO. (b) How can you distinguish between ethanol and ethanal ? (c) How will you convert the following : (i) Toluene to benzoic acid (ii) Ethanol to propan-2-ol (iii) Propanal to 2-hydroxypropanoic acid OR (a) Give IUPAC name of Salicylic acid. (b) Chloroacetic acid is more acidic than acetic acid. Why ? (c) Write the products formed when (CH3)3C–CHO reacts with the following : (i) Zinc amalgam and dilute hydrochloric acid (ii) Concentrated sodium hydroxide solution (iii) Semicarbazide and a weak acid	2019

 

 

Prepared By:

Satyam Kumar Nigam