SARASWATI CHEMISTRY POINT
[C.B.SE. CLASS - XII]
CHEMISTRY (THEORY) – 2012 (COMPTT.)
(SET-I, OUTSIDE DELHI)
Time Allowed: 3 hrs
M.M.: 70
General Instruction:
(i) All questions are compulsory
(ii) Marks for each question are indicated against it.
(iii) Question numbers 1 to 8 are very short answer questions and carry 1 marks each.
(iv) Question numbers 9 to 18 are short answer questions and carry 2 marks each.
(v) Question numbers 19 to 27 are also short answer questions and carry 3 marks each.
(vi) Question numbers 28 to 30 are long answer questions and carry 5 mark each.
(vii) Use log tables if necessary. Use of calculators is not allowed.
Q: 1. What type of stoichiometric defect is
shown by AgBr and AgI?
Q: 2. How is a sol different from an
emulsion?
Q: 3. Which method is employed for
extracting copper from low grade ores
and scraps?
Q: 4. Why does NO2 dimerise?
Q: 5. Give IUPAC name of ionization
isomer of [Ni(NH3)3NO3]Cl.
Q: 6. Give a chemical test of distinguishes
between C2H5Br & C6H5Br.
Q: 7. Write the IUPAC name of the
following:
Q: 8. Formaldehyde does not take part in
Aldol condensation. Why?
Q: 9. State Henry’s law and mention two of
its important applications.
Q: 10. Write the reactions taking place at
cathode and anode in lead storage
battery when the battery is in use.
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What happens on charging the
battery?
Q: 11. What is meant by rate of reactions?
Differentiate between average rate
and instantaneous rate of a reaction.
Q: 12. The extraction of gold by leaching
with NaCN involves both oxidation
and reduction. Justify giving
chemical equations.
Q: 13. (a) Which form of sulphur shows
paramagnetic behaviour ad why?
(b) Fluorine exhibits only-1 oxidation
state whereas other halogens
exhibit +1, +3, +5 or +7 oxidation
states also.
Q: 14. How is the stability of a coordination compound in solution
decided? How is the dissociation
constant of a complex defined?
Q: 15. How would you account for the
following:
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(a) Aniline is a weaker base than
cyclohexylamine.
(b) Methylamine in aqueous medium
gives reddish-brown precipitate
with FeCl3.
Or
How would you account for the
following?
(a) Electrophilic substitution in case
of aromatic amines takes place
more readily than benzene.
(b) Ethanamide is a weaker base than
ethanamine.
Q: 16. Illustrate the following reactions:
(a) Sandmeyer’s reactions
(b) Coupling reactions.
Q: 17. Write down the structures and names
of the products formed when Dglucose is treated with (i)
hydroxylamine (ii) Acetic anhydride.
Q: 18. (a) Name the only vitamin which can
be synthesized in our body. Name
one disease that is caused due to
the deficiency of this vitamin.
(b) State two functions of
carbohydrates.
Q: 19. (a) Some of the glass objects
recovered from ancient
monuments look milky instead of
being transparent. Why?
(b) Iron (II) oxide has a cubic
structure and each side of the unit
cell is 5 Å. If density of the oxide
is 4 g cm-3, calculate the number of
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Fe2+ and O2- ions present in each
unit cell.
[Atomic mass: Fe = 56 u, O = 16 u;
Avogadro’s number = 6.023 × 1023
mol-1]
Q: 20. If N2 gas is bubbled through water at
293 K, how many millimoles of N2
gas would dissolve in 1 litre of water?
Assume that N2 exerts a partial
pressure of 0.987 bar. Given that
Henry’s law constant for N2 at 293 K
is 76.48 k bar.
Or
The partial pressure of ethane
over a saturated solution containing
6.56 × 10-2 g of ethane is 1 bar. If the
solution contains 5.0 × 10-2 g of
ethane, then what will be the partial
pressure of the gas?
Q: 21. What a certain conductance cell was
filled with 0.1 M KCl, it has a
resistance of 85 ohms at 25°C. When
the same cell was filled with an
aqueous solution of 0.052 M
unknown electrolyte, the resistance
was 96 ohms. Calculate the molar
conductance of the electrolyte at this
concentration.
[Specific conductance of 0.1 M KCl
= 1.29 × 10-2 cm-1]
Q: 22. In general it is observed that the rate
of a chemical reaction doubles with
every 10 degree rise in temperature.
If the generalization holds good for
the reaction in the temperature range
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295 K to 305 K, what would be the
value of activation energy for this
reaction?
[R = 8.314 mol-1 K-1]
Q: 23. How are the two types of emulsions
different from one another? Give
suitable example
to justify the difference. State two
applications of emulsions.
Q: 24. Account for the following:
(a) The dipole moment of
chlorobezene is lower than that of
cyclohexyl chloride.
(b) Alkyl halides, though polar, are
immiscible with water.
(c) Grignard’s reagents should be
prepared under anhydrous
conditions.
Q: 25. (a) How would you obtain the
following:
(i) 2-Methylpentan-2-ol from 2methyl-1-pentene.
(ii) Acetophenone from phenol
(b) Write IUPAC name of the
following:
NO2
OC2H5
Q: 26. Explain the term co-polymerization
and give two examples of copolymers
and the reactions for their
preparations.
Q: 27. What are the following substance?
Give one example of each.
PITAM PURA & ROHINI
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(a) Analgesics
(b) Antibiotics
(c) Tranquilization
Q: 28. Account for the following:
(a) Chlorine water loses its yellow
colour on standing.
(b) BrCl3is more stable than BrCl5.
(c) Fluorine does not form oxoacids.
(d) PCl5 acts as an oxidizing agent.
(e) SO2 is an air pollutant.
Or
(a) With the help of chemical
equations explain the principle of
contact process in brief for the
manufacture of sulphuric acid. (No
Diagram)
(b) Account for the following;
(i) Bond dissociation energy of F2
is less than that of Cl2.
(ii) Nitric oxide becomes brown
when released in air.
Q: 29. (a) Describe the preparation of
potassium dichromate from
chromite ore. What is the effect of
change of pH on dichromate ion?
(b) How is the variability in oxidation
stats of transition elements
different from that of nontransition elements? Illustrate
with examples.
Or
(a) Describe the preparation of
potassium permanganate form
pyrolusite ore. What happens when
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acidified potassium permanganate
solution
(b) Account for the following:
(i) Mn2+ compounds are more
stable than Fe2+ compounds
towards oxidation to their +3
state.
(ii) Cr2+ is reducing and Mn3+
oxidizing when both have d4
configuration.
Q: 30. (a) Give chemical tests to distinguish
between the following pairs of
compounds:
(i)Benzene amide and 4aminobenzioic acid
(ii) Methyl acetate and ethyl
acetate
(b) An organic compound with
molecular formula C9H10O forms
2, 4-DNP derivative and reduces
Tollen’s reagent and undergoes
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Cannizzaro’s reaction. On
vigorous oxidation, it gives 1, 2benzenedicarboxylic acid.
Identify the compound and write
chemical equations for the
reactions.
Or
(a) Give chemical test to distinguish
between the following pairs of
compounds:
(b) An organic compound with
molecular formula C5H10O does
not reduce Tollen’s reagent but
forms an addition compound with
sodium hydrogen sulphite and
gives a positive iodoform test. On
vigorous oxidation, it gives
ethanoic acid and propanoic acid.
Identify the compound and write
all chemical equations for the
reactions.
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(4)
SARASWATI CHEMISTRY POINT
[C.B.SE. CLASS - XII]
CHEMISTRY (THEORY) – 2012 (COMPTT.)
(SET-II, OUTSIDE DELHI)
Time Allowed: 3 hrs
M.M.: 70
General Instruction:
(i) All questions are compulsory
(ii) Marks for each question are indicated against it.
(iii) Question numbers 1 to 8 are very short answer questions and carry 1 marks each.
(iv) Question numbers 9 to 18 are short answer questions and carry 2 marks each.
(v) Question numbers 19 to 27 are also short answer questions and carry 3 marks each.
(vi) Question numbers 28 to 30 are long answer questions and carry 5 mark each.
(vii) Use log tables if necessary. Use of calculators is not allowed.
Note: Except for the following questions, all the remaining questions have been asked in Set-I & Set-II.
Q: 1. What type of defect can arise when a
solid is heated?
Q: 2. Write two applications of adsorption.
Q: 3.What is the basic principle of zone
refining of metals?
Q: 4. Why is ICI more reactive than I2?
Q: 5. Write down the formula of:
Tetraamineaquachloridocobalt (III) chloride.
Q: 6. Arrange the following in increasing
order of boiling point:
(a) CH3CH2CH2CH2Br
(b) (CH3)3C . Br
(c) (CH3)2 . CH . CH2 . Br
Q: 7. Write the IUPAC name of the
following:
O
CH3
Q: 8. Aldehydes and Ketones have lower
boiling points than corresponding
alcohols. Why?
PITAM PURA & ROHINI
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Q: 9. Why do gases nearly always tend to be
less soluble in liquids as the
temperature is raised?
Q: 10. Write down the structures and names
of the products formed when Dglucose is treated with
(i) Bromine water
(ii) Hydrogen Iodide (Prolonged
heating)
Q: 11. How is the stability of a coordination compound in solution
decided? How is the dissociation
constant of a complex defined?
Q: 20. (a) How many coulombs are required
to reduce 1 mole Cr2O72- to Cr3+?
(b) The conductivity of 0.001 M
acetic acid is 4 × 10-5 S/m.
Calculate the dissociation
constant of acetic acid if Λ0m for
acetic acid is 390 cm2 mol-1.
Q: 21. What are the following substances?
Give one example of each.
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SARASWATI CHEMISTRY POINT
(i) Broad Spectrum antibiotics
(ii) Narcotic analgesics
(iii) Synthetic detergents
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Q: 22. Explain the term co-polymerization
and give two examples of
copolymers and the reactions for
their preparations.
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(6)
SARASWATI CHEMISTRY POINT
[C.B.SE. CLASS - XII]
CHEMISTRY (THEORY) – 2012 (COMPTT.)
(SET-III, OUTSIDE DELHI)
Time Allowed: 3 hrs
M.M.: 70
General Instruction:
(i) All questions are compulsory
(ii) Marks for each question are indicated against it.
(iii) Question numbers 1 to 8 are very short answer questions and carry 1 marks each.
(iv) Question numbers 9 to 18 are short answer questions and carry 2 marks each.
(v) Question numbers 19 to 27 are also short answer questions and carry 3 marks each.
(vi) Question numbers 28 to 30 are long answer questions and carry 5 mark each.
(vii) Use log tables if necessary. Use of calculators is not allowed.
Q: 1. Why does LiCl acquire pink colour
when heated in Li vapours?
Q: 2. Why do true solutions not show
Tyndall effect?
Q: 3. Although thermodynamically feasible,
in practice, magnesium metal is not
used for reduction of Alumina in the
metallurgy of aluminium. Why?
Q: 4. Why is BiH3 the strongest reducing
agent amongst all the hydrides of
group 15 elements?
Q: 5. Indicate the types of isomerisms
exhibited by the complex
[Co(NH3)5 (NO2)] (NO3)2.
Q: 6. Write the IUPAC name of the
following:
CH3
CH3
H
PITAM PURA & ROHINI
H CH3
SUDHIR PANWAR
Q: 7. Give the structure and IPUAC name of
the product formed when propanone is
reacted with methylmagnesium
bromide followed by hydrolysis.
Q: 8. Write the structure of the product
formed in the following reaction:
O
C
+ C2H5
Cl Anhydrous AlCl3
Q: 9. [Fe (H2O)6]3+ is strongly paramagnetic
whereas [Fe(CN)6]3- is weakly
paramagnetic. Explain (At. No. Fe =
26]
Q: 10. How is XeO3 obtained? Write the
related chemical equations. Draw the
structure of XeO3.
Q: 11. (a) Name the only vitamin which can
be synthesized in our body. Name
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SARASWATI CHEMISTRY POINT
on disease that is caused due to
the deficiency of this vitamin.
(b) State two functions of
carbohydrates.
Q: 19. (Antilog of 6.5 = 3.162 × 106; of 8.0
= 10 × 108; of 8.5 = 3.162 ×108)
The cell in which the following
reaction occurs:
2 Fe3+ (aq) + 2 I¯ (aq) → 2 Fe2+ (aq) +
I2 (s)
Has E°cell = 0.236 V at 298 K.
Calculate the standard Gibbs energy
and the equilibrium constant of the
cell reaction.
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Q: 20. (a) A reaction is first order in A and
second order in B.
(i) Write differential rate
equation.
(ii) How is rate affected when
concentration of B is tripled?
(iii) How is rate affected when
concentration of both A and B
is doubled?
(b) What is molecularity of a
reaction?
Q: 21. What is an adsorption isotherm?
Describe Freundlich adsorption
isotherm.
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