The document contains 18 organic chemistry word problems involving the structures and reactions of various organic compounds. Problem 1 involves compounds A-E with molecular formulas C8H8O, C7H6O2, etc. and their reactions with reagents like 2,4-DNP and iodine. Problem 2 identifies a compound with the molecular formula C9H10O based on its reactions. Problem 3 involves the hydrolysis of compound A (C8H16O2) to compounds B and C and the oxidation of C.

1. Word Problems
Organic Chemistry
Class 12

2. • Q.1 An organic compound (A) with molecular
formula C8H8O forms an orange-red
precipitate(B) with 2,4-DNP reagent and gives
yellow precipitate( C ) on heating with iodine in
the presence of sodium hydroxide along with a
colourless compound( D ) . ( A ) neither reduces
Tollens’ or Fehlings’ reagent, nor does it
decolourise bromine water or Baeyer’s reagent.
On drastic oxidation of ( A ) with chromic acid,
it gives a carboxylic acid (E) having molecular
formula C7H6O2. Deduce the structures of
organic compounds (A) to (E) and explain the
reactions involved.

3. • An organic compound with the molecular
formula C9H10O forms 2,4-DNP derivative,
reduces Tollens’ reagent and undergoes
Cannizzaro reaction. On vigorous oxidation, it
gives 1,2-benzenedicarboxylic acid. Identify
the compound.

4. • Q.3 An organic compound (A) (molecular
formula C8H16O2) was hydrolysed with dilute
sulphuric acid to give a carboxylic acid (B)
and an alcohol (C). Oxidation of (C) with
chromic acid produced (B). (C) on
dehydration gives but-1-ene. Write equations
for the reactions involved.

5. • .4 An organic compound contains 69.77%
carbon, 11.63% hydrogen and rest oxygen.
The molecular mass of the compound is 86. It
does not reduce Tollens’ reagent but forms
an addition compound with sodium
hydrogensulphite and give positive iodoform
test. On vigorous oxidation it gives ethanoic
and propanoic acid. Write the possible
structure of the compound.

6. • 5 Primary alkyl halide C4H9Br (a) reacted with
alcoholic KOH to give compound (b).
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 which is different from the compound
formed when n-butyl bromide is reacted with
sodium. Give the structural formula of (a)
and write the equations for all the reactions.

7. • Q.6 An organic compound (A) with molecular
formula C5H8O2 is reduced to n-pentane on
treatment with Zn-Hg/ HCl . ‘A’ forms a
dioxime with hydroxylamine and gives a
positive iodoform test and Tollen’s
test.Identify the compound ‘A’ and deduce
its structure.

8. • Q.7 An organic compound (A) with molecular
formula C8H8O gives a positive DNP and
iodoform test . It does not reduce Tollens’ or
Fehlings’ reagent and does not decolourise
bromine water also. On oxidation with
Chromic acid(H2CrO4) , It gives carboxylic acid
(B) with a molecular formula C7H6O2 . Deduce
the structures of organic compounds (A) and
(B).

9. • 8 An unknown aldehyde ‘A’ on reacting with
alkali gives a β-hydroxy aldehyde , which losses
water to form an unsaturated aldehyde , 2-
butenal . Another aldehyde ‘B’ undergoes
disproportionation reaction in the presencence
of conc.alkali to form products ‘C’ and ‘D’ . ‘C’ is
an aryl alocohol with a formula C7H8O.
• (i) Identify A and B
(ii) Write the sequence of reactions involved
• (iii) Name the product , when B
reacts with Zinc amalgam and hydrochloric acid .

10. • Q.9 A compound ‘X’ (C2H4O ) on oxidation gives
‘Y’ (C2H4O2) . ‘X’ undergoes haloform
reaction.On treatment with HCN ‘X’ forms a
product ‘Z’ which on hydrolysis gives 2-hydroxy
propanoic acid .
• (i) Write down structures of ‘X’ and ‘Y’
(ii) Name the product when ‘X’ reacts with dil
NaOH
• (iii) Write down the equations for the
reactions involved.

11. • 10 An optically active compound having
molecular formula C7H15Br reacts with
aqueous KOH to give a racemic mixture of
products .Write the structures of the
compounds

12. • Q.11 A compound (A) with molecular formula
C5H12O , on oxidation forms compound (B)
with molecular formula C5H10O .The
compound (B) gives iodoform test ,but does
not reduce ammoniacal silver nitrate
solution.(B) on reduction with amalgamated
zinc and conc.HCl gives compound (C)with
molecular formula C5H12. Identify (A),(B),(C),
write down the chemical reaction involved .

13. • Q.12An organic compound (A) with a molecular
formula C3H6O2 when treated wit h excess of
NH3 and then heated formed B (C3H7ON). B on
treatment with P2O5 formed C with molecular
formula C3H5N. C on complete acid hydrolysis
formed A . C on reduction with complex metal
hydride formed a basic nitrogeneous compound
D with molecular formula C3H9N . D on
treatment with HNO2 formed an alcohol ‘E’
(C3H8O).E on oxidation gave A . Give structures
of A to E and write reactions

14. • .13An organic compound “A” has a molecular
formula C3H7O2N on reaction with Fe and
Conc.HCl give a compound “B” of molecular
formula C3H9N . Compound “B” on treatment
with NaNO2 and HCl give another compound “C”
of molecular formula C3H8O.The compound “C”
gives effervescence with Na.On oxidation with
CrO3, the compound “C” gives a saturated
aldehyde containing three carbon atoms
.Deduce the structures of “A”, “B” and “C” and
write the chemical equations for the reactions
involved.

15. • 14 A compound ‘A’ of molecular formula
C7H7NO. On treatment with Br2 and NaOH it
gives B .B gives a foul smelling substance C
on treatment with CHCl3 and KOH . B on
treatment with NaNO2 and HCl at 00C and
mixing with alkaline phenol give a red dye
D.Identify A to D

16. • Q.15 An organic compound “A” which has
characteristic odour, on treatment with
NaOH forms two compounds “B” and “C”
.Compound “B” has a molecular formula
C7H8O which on oxidation gives back
compound “A’.Compound “C” is the sodium
salt of an acid .”C” when heated with
sodalime yields an aromatic
hydrocarbon”D”.Deduce the structure
A,B,C,D .

17. • Q.16 An organic compound “A” has a
molecular formula C5H10O.It does not reduce
Fehling’s Solution but forms a bisulphite
compound .It also positive iodoform
test.What is the possible structure of “A”?
Explain your reasoning which helped to
arrive at the structure.

18. • 17 A compound “A” has a molecular formula
C5H10O gave a positive 2,4-DNP test but a
negative Tollen’s test. It was oxidized to
carboxylic acid “B” with molecular formula
C3H6O2 when treated with alkaline KMnO4
under vigorous condition .Sodium salt of ‘B”
gave a hydrocarbon “C” on Kolbe’s
electrolytic reduction Identify A,B and C and
write chemical equations for the reaction.

19. • Q.18 An organic compound ‘A’ having
molecular formula ,C6H6O gives a
characteristic colour with aqueous FeCl3
solution.’A’on treatment with CO2 and NaOH
at 400K under pressure gives ‘B’ which on
acidification gives a compound ‘C’ . ‘C’ reacts
with acetyl chloride to give ‘D’ which is a
popular pain killer .Deduce the structures of
A,B,C and D .