Organic Problems from Carbonyl compounds

 

Q No. 70. c / 70. a

1. Compound (A) of molecular formula C₇H₈ when treated with air in presence of V₂O₅ at 773 K gives a compound  (B) of molecular formula C₇H₆O, which has the smell of bitter almonds. Alkaline KMnO₄ oxidises compound (B) to (C) of molecular formula C₇H₆O₂.  Compound (B) on treatment with N₂H₄ and KOH gives back compound (A). Identify (A), (B) & (C) and explain the reactions. J–10

ANSWER

(A) Toluene

(B) Benzaldehyde

(C) Benzoic acid

2. An organic compound A (C₇H₈) on oxidation by air in the presence of V₂O₅ at 773 K gives B (C₇H₆O), which reduces Tollen's reagent. B when heated with acetic anhydride and sodium acetate gives C (C₉H₈O₂). Identify A, B and C. Write the reactions. M–11

ANSWER

(A) Toluene

(B) Benzaldehyde

(C) Cinnamic acid

3. An organic compound A (C₇H₆O) reduces Tollen's reagent. On treating with an alkali compound A forms B and C. B on treating with sodalime forms benzene and C (C₇H₈O) is an antiseptic. Identify compounds A, B and C. Explain the reactions. O–06

ANSWER

(A) Benzaldehyde

(B) Benzoic acid

(C) Benzyl alcohol

4. Compound A with molecular formula C₇H₆O reduces Tollen's reagent and also gives Cannizzaro reaction. A on oxidation gives the compound B with molecular formula C₇H₆O₂. Calcium salt of B on dry distillation gives the compound C with molecular formula C₁₃H₁₀O. Find A, B and C. Explain the reaction. M–08

ANSWER

(A) Benzaldehyde

(B) Benzoic acid

(C) Benzophenone

5. An organic compound (A) of molecular formula C₇H₆O is not reduced by Fehling's solution but will undergo Cannizzaro reaction. Compound (A) reacts with Aniline to give compound (B). Compound (A) also reacts with Cl₂ in the presence of catalyst to give compound (C). Identify (A), (B) and (C) and explain the reactions. M–06

ANSWER

(A) Benzaldehyde

(B) Benzanilide

(C) m-Chloro benzaldehyde

6. An aromatic compound (A) with molecular formula C₇H₆O has the smell of bitter almonds. (A) reacts with Cl₂ in the absence of catalyst to give (B) and in the presence of catalyst compound (A) reacts with chlorine to give (C). Identify (A), (B) and (C). Explain the reactions. M–09

ANSWER

(A) Benzaldehyde

(B) Benzoyl chloride

(C) m-Chloro benzaldehyde

7. An organic compound A (C₇H₆O) forms a bisulphate. A when treated with alcoholic KCN forms B (C₁₄H₁₂O₂) and A on refluxing with sodium acetate and acetic anhydride forms an acid C (C₉H₈O₂). Identify A, B and C. Explain the conversion of A to B and C. J–07

ANSWER

(A) Benzaldehyde

(B) Benzoin

(C) Cinnamic acid

8. An aromatic aldehyde (A) of molecular formula C₇H₆O which has the smell of bitter almonds on treatment with (CH₃CO)₂O and CH₃COONa to give compound (B) which is an aromatic unsaturated acid. (A) also reacts with (A) in the presence of alc. KCN to give dimer (C). Identify (A). (B) and (C). Explain the reactions. O–07

ANSWER

(A) Benzaldehyde

(B) Cinnamic acid

(C) Benzoin

9. Compound A (C₂H₄O) reduces Tollen's reagent. A on treatment with zinc amalgam and conc. HCl gives compound B. In presence of conc.H₂SO₄ A forms a cyclic structure C which is used as hypnotic. Identify A, B and C. Explain the reactions. J–11

ANSWER

(A) Acetaldehyde

(B) Propane

(C) Paraldehyde

10. Compound (A) with molecular formula C₂H₄O reduces Tollen's reagent. (A) on treatment with HCN gives compound (B). Compound (B) on hydrolysis with an acid gives compound (C) with molecular formula C₃H₆O₃. Compound (C) is optically active. Compound (C) on treatment with Fenton's reagent gives compound (D) with molecular formula C₃H₄O₃. Compounds (C) and (D) give effervescence with NaHCO₃ solution. Identify the compounds (A), (B), (C) and (D) and explain the reactions. M–10 / O–11

ANSWER	(A) Acetaldehyde	(B) Acetaldehyde cyanohydrin
	(C) Lactic acid (Optically active)	(D) Pyruvic acid

11. An organic compound A (C₂H₄O) with HCN gives B (C₃H₅ON). B on hydrolysis gives C (C₃H₆O₃) which is an optically active compound. C also undergoes iodoform test. What are A, B and C? Explain the reactions. O–11 / M–10

ANSWER

(A) Acetaldehyde

(B) Acetaldehyde cyanohydrin

(C) Lactic acid (Optically active)

12. Compound A having the molecular formula C₂H₄O reduces Tollen's reagent. A on treatment with HCN followed by hydrolysis gives the compound B with molecular formula C₃H₆O₃. Compound B on oxidation by Fenton's reagent gives the compound C with the molecular formula C₃H₄O₃. Find A, B and C. Explain the reactions. J–08 / O–08

ANSWER

(A) Acetaldehyde

(B) Lactic acid

(C) Pyruvic acid

13. An aromatic compound (A) (C₂H₄O) reduces Tollen's reagent. (A) reacts with HCN and followed by hydrolysis in acid medium gives (B) (C₃H₆O₃) which is optically active. Compound (B) on reaction with Fenton's reagent forms (C) (C₃H₄O₃).  This answers iodoform reaction. Identify (A), (B) and (C). Write the reactions involved. O–08 / M–08

ANSWER

(A) Acetaldehyde

(B) Lactic acid

(C) Pyruvic acid

14. An organic compound A of molecular formula C₃H₆O on reduction with LiAlH₄ gives B. Compound B gives blue colour in Victor Meyers test and also forms a chloride C with SOCl₂. The chloride on treatment with alcoholic KOH gives D. Identify A. B. C and D and explain the reactions. M–07

ANSWER	(A) Acetone	(B) iso-Propyl alcohol
	(C) iso-Propyl chloride	(D) Propylene

15. Compound A of molecular formula C₃H₆O does not reduce Tollen's reagent and Fehling's solution. Compound A undergoes Clemrnensen reduction to give compound B of molecular formula C₃H₈. Compound A in the presence of conc.H₂SO₄ condenses to give an aromatic compound C of molecular formula C₉H₁₂. Identify A, B and C. Explain the reactions. M–12

ANSWER

(A) Acetone

(B) Propane

(C) Mesitylene / 1, 3, 5-Trimethyl benzene

17. An organic compound (A) with molecular formula C₃H₆O undergoes Iodoform reaction. Two molecules of compound (A) react with dry HCl to give compound (B) (C₆H₁₀). Compound (B) reacts with one more molecule of compound (A) to give compound (C) (C₉H₁₄O). Identify (A), (B), (C) and (D). Explain the reactions. O–10

ANSWER

(A) Acetone

(B) Mesityl oxide

(C) Phorone

18. Compound A (C₃H₆O) does not reduce Tollen's reagent but undergoes haloform reaction. Compound A undergoes dehydration reaction in the presence of dry HCl to give compound B (C₆H₁₀O). Three molecules of compound A undergoes condensation reaction in the presence of conc.H₂SO₄ to give a cyclic hydrocarbon (C). Identify A, B and C. Give the reactions. J–12

ANSWER

(A) Acetone

(B) Mesityl oxide

(C) Mesitylene / 1, 3, 5-Trimethyl benzene

19. An organic compound (A) C₂H₃OCl on treatment with Pd and BaSO₄ gives (B) C₂H₄O which answers iodoform test. (B) when treated with conc. H₂SO₄ undergoes polymerization to give (C) a cyclic compound. Identify (A), (B) and (C) and explain the reaction. O–09

ANSWER

(A) Acetyl chloride

(B) Acetaldehyde

(C) Paraldehyde

20. An organic compound A (C₂H₃N) on reduction with SnCl₂ / HCl gives C₂H₄O which reduces Tollen’s reagent. Compound B on reduction with N₂H₄ / C₂H₅ONa gives C (C₂H₆). Identify the compounds A, B and C. Explain the reactions involved. O–12

ANSWER

(A) Methyl cyanide

(B) Acetaldehyde

(C) Ethane

21. An organic compound (A) of molecular formula C₂H₆O on treatment with PCl₅ gives compound (B). Compound (B) reacts with KCN to give a compound (C) of molecular formula C₃H₅N which undergoes acid hydrolysis to give compound (D) which on treatment with Soda lime gives a hydrocarbon. Identify (A), (B), (C) and (D) and explain the reactions. J–06

ANSWER	(A) Ethyl alcohol	(B) Ethyl chloride
	(C) Ethyl cyanide	(D) Propanoic acid

22. An organic compound A (C₇H₆O₂) reacts with NH₂OH forming a crystalline compound. On warming with NaOH it forms two compounds B and C. ‘B’ is neither soluble in NaOH nor in HCl but can be oxidised to A. The compound ‘C on treatment with Conc. HCl forms acid ‘D’ which on treating with soda lime gives ‘phenol’. Identify A to D. 0

ANSWER	(A) o-Hydroxy benzaldehyde / Salicylaldehyde	(B) o- Hydroxy benzyl alcohol
	(C) Sodium salicylate	(D) Sodium Benzoate

MOLECULAR FORMULA & COMPOUNDS