2017 MODEL CHEMISTRY XII (043) CBSE PAPER SET -1
CLASS - XII
CHEMISTRY MODEL PAPER – (043)—2017
SET-1
Time : Three hour Max. Marks : 70
General Instructions
:-
1.All questions are compulsory.
2. Question No. 1-5 are very short answer
questions and carry 1 mark each.
3. Question No. 6-10 is short answer
questions and carries 2 marks each.
4. Question No. 11-22 is also short answer
questions and carries 3 marks each.
5. Question No. 23 is value added questions
and carry 4 marks.
6. Question No. 24-26 carry 5 marks
7. Use log tables if necessary, use of
calculators is not allowed.
Q1. What desease may
caused if a person having defeciency of
vitamin- E 1
Q2. What are the
physical states of dispersed phase and dispersion medium of froth? 1
Q 3. Write the
balanced equation for complete hydrolysis of XeF6 . 1
Q4. Write the
structure of : pent - 3 - en - 2 - one 1
Q5. A compound
contains two types of atoms - X and Y. It crytallises in a cubic lattice with
atom X at
the
corners of the unit cell and atomsY at the body centres. What is the simplest
possible formula
of this compound?
1
Q6. What is the Van’t Hoff factor for a
compound which undergoes tetramerization in an organic
solvent upto 30%. 2
Q 7. (i)An ore sample
of galena (PbS) is contaminated with zinc blende (ZnS). Name one chemical
which can be used to concentrate galena
selectively by froth floatation method. 2
(ii) How van Arkel process used
to purified the Zirconium .
Q 8.Drow the
structure of XeOF 4 and H2 S2 O8. 2
Q9. Ethylene glycol
(molar mass = 62 g mol¯ 1) is a common automobile antifreeze. Calculate the
freezing point of a solution
containing 12.4g of this substance in 100 g of water. Would it be
advisable to keep this substance in the car radiator during summer?
Given : Kf for water = 1.86K
kg/mol Kb for water = 0.512K kg/mol 2
Q 10. If a reaction
complete 55% in 5 min. How much time it will take to complete 85%.
Q11.(i)How much faraday
will be required to deposit 54 gm of
aluminium from molten Alcl3 .
(ii)How Ni-cd battery is usefull ten
other. 3
Q12. (i)Write the
monomer of starch and cellulose.
(ii)Give chemical equation when glucose react
with acetic anhydride.
(iii)What is glycosidic
linkage.? 3
Q13. (i) What changes
occur in the nature of egg proteins on boiling?
(ii) Define alpha helix and beta
pleated structure of protein. 3
Q14. (i)Describe the mechanism
methyl magnesium bromide with acetaldehyde
(ii)Give a mechanisn of reaction when propene
undergoes on ozonolysis? 3
Q15. Write short
notes on the following name reaction : 3
(i) Carbylamine reaction
(ii)Cannizaro reaction
(iii)Halloform reaction.
Q16. (a)Give chemical
tests to distinguish between compounds in each of the following pairs:
(i) Phenol and Ethyl alcohol
(ii) Butane-2 -ol and 2 Methyl
propan - 2- ol 2
(b)Phenol show acic charecor.explain? 3
Q 17. Predict, giving
reasons, the order of basicity of the following compounds in
(i) gaseous phase and
(ii) in aqueous solutions
CH3NH2 ,(CH3)2NH ,(CH3)3N and C2 H5 NH2,
(C2 H5)2 NH
, (C2 H5 )3N 3
OR
Account for the following: (a) Aniline does
not undergo Friedel Crafts alkylation (b) Although - NH2
group
is an ortho and para-directing group, nitration of aniline gives alongwith
ortho &
paraderivatives meta-derivative also.
Q 18. Give reasons
for the following :
(i) At higher altitudes, people suffer from a disease called anoxia. In
this disease, they become
weak and cannot think clearly.
(ii) When mercuric iodide is added to an aqueous solution of KI, the
freezing point is raised.
(iii)Define hardy schulze rule. 3
Q19.(i) An element X
with an atomic mass of 50g/mol has density of 6.02g cm-3. If
the edge length of
its cubic unit cell is 400 pm, identify
the type of cubic unit cell. Calculate the radius of an atom of
this element.
(ii) Define what is
antiferomagnectic substances.
Q20. Write names of
monomer/s of the following polymers and classify them as addition or
condensation polymers.
(a) PHBV (b) Bakelite (c) Nylon-6 3
Q21. (a) Give the
IUPAC name of :
[Co(cl)6]SO4
(b) Give the number of unpaired electrons in the above following
complex and also fine the
hybridisation. 3
Q22. Explain the
following observations:
(a) What is tindal effect.
(b) Difference beetwen lyophilic
and liophobic substances.
(c) Write only langmuir adsoprtion isotherms.? 3
Q23. Sudha’s mother
received a phone call on Monday morning from a close relative stating that
three of them would be coming over for lunch. Sudha’s mother noticed
that she did not have
enough curd to serve the guests. Sudha a class XII student suggested
that her mother could warm
the milk from the refrigerator or keep it under direct sunlight and
curdle it.
a) Why do you think Sudha suggested the above
methods?
b) Will it be helpful if her mother followed
Sudha’s suggestion?
c) What values are associated with Sudha’s
suggestion?. 3
Q 24. The
decomposition of N2 O5 (g) is a first order reaction with
a rate constant of 5 x 10-4 sec-1 at
45o C. i.e.
2N2 O5 (g)---à
4NO2 (g) + O2 (g).
If initial concentration of N2
O5 is 0.25M, calculate its concentration after 2 min. Also calculate
half
life for decomposition of N2 O5
(g).
(b) For an elementary reaction the rate of appearance of C at time ‘t’
is 1.3 x 10-4 mol -1 s-1 .
Calculate at this time
(i) rate of the reaction. (ii)
Rate of disappearance of A. 5
OR
(a) An
organic compound ‘A’ with molecular formula C5 H8 O2
is reduced to n-pentane on treatment
with Zn-Hg/ HCI. ‘A’ forms a dioxime with hydroxylamine and gives a
positive lodoform test and Tollen’s test. Identify the compound A and deduce
its structure.
(b) Write the chemical equations for the following conversions:
(i) Ethyl benzene to benzene
(ii) Acetaldehyde to butane - 1, 3 - diol
(iii) Acetone to propene
Q25. (a) Which of the following two compounds
would react faster by SN2
1 – bromobutane or 2
– bromobutane and why.?
(b) Allyl chloride is more reactive than n - propyl chloride towards
nucleophilic substitution reaction.
Explain why?
(c) Haloalkanes react with KCN to give alkyl cyanide as main product
while with AgCN give different
compound.?
(d) Transition metals have high
enthalpies of atomization.
(e) Among the lanthanoids,
Ce(III) is easily oxidised to Ce(IV). isocyanide as main product. Give reason.
OR
(a) For a certain
chemical reaction
A + 2B ------------à 2C + D
The experimentally obtained
information is tabulated below.
Experiment [A]0 [B]0 Initial rate
1. 0.30 0.30 0.096
2. 0.60 0.30 0.384
3. 0.30 0.60 0.192
4. 0.60 0.60 0.768
For this reaction
(i) Derive the order of
reaction w.r.t. both the reactants A and B.
(ii) Write the rate law.
(iii) Calculate the value of rate constant k
(iv) Write the expression for the rate of
reaction in terms of A and C
(b) Give chemical equation which occur
(a) K2 Cr2 O7
+ H 2SO 4 + C2H5OH-----------à
(b)
XeF 4 + O2 F2 ----------à
(c) 2H3
PO3 ----------^------à
5
Q 26. Give reasons
for the following:
(a) ClF3 is known but Fcl3 does not known. ?
(b) NO2 demerises to
form N2 O4 ?
(c) ICl is more reactive than I2 ?
(d)Are all P-cl bond in Pcl5 unequal.explain?
(e)Only Xe from inert gases make compound with O and F atom. While other
gases does not. 5
OR
An element ‘A’ exists as a yellow
solid in standard state. It forms a volatile hydride ‘B’ which is a foul
smelling gas and is extensively used in qualitative analysis of salts. When
treated with oxygen, ‘B’ forms an oxide ‘C’ which is a colourless, pungent smelling
gas. This gas when passed through acidified KMnO4 solution, decolourises it.
‘C’ gets oxidized to another oxide ‘D’ in the presence of a heterogeneous
catalyst. Identify A,B,C,D, and also give the chemical equation of reaction of
‘C’ with acidified KMnO4 solution and for conversion of ‘C’ to ‘D’.
DR SUDHIR TOMAR
Comments
Post a Comment