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ALLAI-ACADEMY-ORGANIC PROBLEMS FOR DEC.2019-BY MR MANDIA 0689154703/0757983103
ORGANIC PROBLEMS FORM FIVE/SIX
1. An organic compound ‘A’ which has characteristic odour, on treatment with NaOH
forms two compounds ‘B’ and ‘C’ compound ‘B’ has the molecular formula C7H8O
which on oxidation gives back compound ‘A’. compound ‘C’ is the sodium salt of an
acid which heated with soda lime yields an aromatic hydrocarbon ‘D’. Deduce
A,B,C,D.
2. An organic compound ‘A’ is resistant to oxidation forms an oxidation forms a
compound B(C3H3O) on reduction, B reacts with HBr to form a bromide ‘C’ which
on treatment with alcoholic KOH forms an alkane ‘D’ (C3H6). Deduce A,B,C,D.
3. Eherial solution of an organic compound ‘A’ when heated with magnesium gave ‘B’
on treatment with ethanol followed by acid hydrolysis gave 2-propanol. Identify the
compound A. what is B known as?
4. Primary alkyl halide C4H9Br (A) reacted with alcoholic KOH to give compound (B) is
reacted with HBr to give (c) which is an isomer of (A).when (A) is reacted with
sodium metal it gives compound (D) C8H18 that was different from the compound
formed when n-butyl bromide is reacted with sodium. Give the formula of A and
write equations.
5. A chloro compound ‘A’ on reduction with Zn – Cu and alcohol gives the hydro
carbon (B) with five carbon atom. When ‘A’ is dissolved in ether and treated with
sodium 2,2,5,5 tetra methyl hexane is formed structure of A and B?
6. An aromatic compound, ‘A’ on treatment with aqueous ammonia and heating forms
compound, ‘B’ which on heating with Br2 and KOH forms a compound, ‘C’ of
molecular formula C6H7N. Write the structures and IUPAC names of compounds A,
B and C.
7. A alcohol A (C4H10O) on oxidation with acidified potassium dichromate to gives
carboxylic acid B (C4H8O2). Compound A when dehydrated with conc. H2SO4 at 443
gives compound C. Treatment of C with aqueous H2SO4 gives compound D.
(C4H10O) which is an isomer of A. compound D is resistant to oxidation but
compound A can be easily oxidized. Identify A, B, C and D and write their structures.
8. An organic compound A having molecular formula C6H6O gives a characteristic
colour with aqueous FeCl3. When A is treated with NaOH and CO2 at 400 K under
pressure compound B is obtained. Compound B on acidification gives, compound C
which reacts with acetyl chloride to form D, which is a popular pain killer. Deduce
the structure of A,B,C and D. What is the popular name of Drug D?
9. An organic compound (A) having molecular formula C5H10O gives a positive DNP
test. It does not reduce Tollen’s Reagent but forms an addition compound with
sodium hydrogen sulphite. On reaction with I2 in alkaline medium, it forms a yellow
precipitate of compound B and another compound C having molecular formula
C4H7O2Na. On oxidation with KMnO4 [A] forms two acids D and E having molecular
formula C3H602 and C2H4O2 respective. Identity A,B,C,D and E.
10. An organic compound (A) has molecular formula (C5H10O). It does not reduce
Tollens’ reagent but forms an orange precipitate with 2.4-DNP reagent. It forms a
carboxylic acid (B) with molecular formula (C3H6O2) when treated with alkaline 2
ALLAI-ACADEMY-ORGANIC PROBLEMS FOR DEC.2019-BY MR MANDIA 0689154703/0757983103
KMnO4 and a yellow precipitate on treatment with NaOH and I2. On oxidation under
vigorous conditions gives ethanoic acid and propanoic acid. Sodium salt of (B) gave a
hydrocarbon (C) in Kolbe’s Electrolytic Reduction. Identity (A), (B) and (C) and
write the reactions involved.
11. A neutral compound P,C9H12O2,Fumes when treated with phosphorous penta-chloride
and, when heated with acidified sodium dichromate solution another neutral
compound, Q, is formed. Q produces a characteristic orange –red precipitate with a
solution of 2,4 dinitrophenyl hydrazine but Q does not react with ammoniacal
solution of silver oxide. P a yellow precipite with iodine and alkali and if the filtrate
from this reaction is a acidified, an acid R, C8H8O3, is produced. R on boiling with
hydrogen iodine gives a further acid, S.A familiar smell of oil of winter green is
produced if S is warmed with methanol contain a little concentrated sulphuric acid as
catalyst. Deduce the nature of compound P,Q,R and S and explain full all the reaction
between and ethanoic anhydride?
12. 60.0cm3
of gaseous hydrocarbon, A, was exploded with 400cm3
of oxygen. On
cooling to room temperature and pressure, the residual gas occupied a volume of
280cm3
. On shaking with aqueous potassium hydroxide, the volume left occupied
40cm3. Treatment of compound A, with hydrogen chloride gas, yielded a compound
B. When B was treated with aqueous sodium hydroxide, compound C was obtained
which when reacted with ethanoic acid, produced a compound D. Compound D had
a. Determine molecular formula of A and write the structure of the possible isomers
of this compound
b. Give names and structural formulae of B, C and D and explain, with the aid of
equations, the reason for your deductions.
13. Write the formulae for the organic products formed in these reactions
(a) C2H5COCH3 + C6H5NHNH2
(b) C6H5CHO + LiAIH4
(c) C2H5CHO + [Ag(NH3)2] +
(aq)
(d) C6H5CH = CHCHO + H2 d
(e) C6H5CH = CHCHO + NaBH4
(f) C2H5COCH3 + LiAIH4
14. State two reactions of aldehydes which are also characteristic of ketones and two
which are not shared by ketones. What is the reason for the difference?
15. Of the compounds A, B, C and D, which compound
(a) Undergoes the aldol reaction
(b) Gives a positive iodo form test
(c) Undergoes the Cannizzaro reaction and
(d) Is reduced to a secondary alcohol?
A, CH3CH2COCH2CH3 B, CH3CH2CH2CH2CHO
C, C6H5COCH3 D, C6H5CHO
16. A liquid, A, of formula C7H6O, was refluxed with concentrated aqueous sodium
hydroxide. Ethoxyethane extraction of the resulting solution, followed by drying and
distillation, gave as the main product a liquid, B, of boiling temperature 205˚C. B
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