December 24, 2012

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

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