SAMPLE PAPER -9 Time Allowed: 3 Hrs

SAMPLE PAPER -9
CLASS-XII
Time Allowed: 3 Hrs
SUB - CHEMISTRY
Maximum Marks: 70
General Instructions:
1. All questions are compulsory.
2. Question No. 1-8 are very short answer questions and carry 1 mark each.
3. Question No. 9-18 are short answer questions and carry 2 marks each.
4. Question No. 19-27 are also short answer questions and carry 3 marks each.
5. Question No. 28-30 are long answer questions and carry 5 marks each.
6. Use log tables if necessary, use of calculators is not allowed.
1. Name the vitamins whose deficiency is responsible for night blindness &
poor coagulation of blood?
2. Give example for Thermoplastics.
3. Name a food preservative which is used by food producers.
4. Write the IUPAC name of
CH3 – CH(CH3) – CO – CH(CH3) – CHO
5. What is depressant? Give example?
6. Write any one function of DNA?
7. What causes Brownian movement in a colloidal solution?
8. Give example for ferromagnetic substance?
9. Why is aniline converted into acetanilide before nitration?
10. Distinguish between
a. DNA &RNA
b. α Glucose &β -Glucose
Or
State the difference between
α Helix and β -Pleated sheet structure
11. Define Henry’s law? Write any one application of Henry’s law?
12. Out of C and CO, Which is a good reducing agent for extraction of Zn from ZnO?
13. Give two examples for bio degradable polymer?
14. How do antiseptics and disinfectants differ in their uses?
15. A first order reaction has a rate constant 1.15 X 10-3 S-1.
How long will 10g of this reactant take to reduce to 5g?
16. Write short note on
a. Reimer Tiemann reaction
b. Williamson’s synthesis
www.cpprashanthschemistry.com
Page 1
17. Complete the following
1. C6H5OH + Br2(aq)
2. C6H5NH2 +C6H5N2Cl
18. Account for the following
1. HCHO gives Cannizaro’s reaction . Where as CH3CHO doesn’t
2. Write chemical test to distinguish Phenol and benzoic acid.
19. What happens when
a. Beam of light is passed through Fe(OH)3 solution
b. KCl is added to Fe(OH)3s
c. River and Sea meet
20. Acompound A is extensively used as an insecticide as well as pesticide. Give its IUPAC
name.Write its structure & give reasons why is it banned?
21. Give reason
a. White P is more reactive than red P
b. NO2 dimerises to form N2O4
c. CN- is known but CP- is not known
(OR)
Arrange the following in the increasing order of
a. HCL, HF, HBr, HI (acidic strength)
b. HCl, HBr, HF, HI (Boiling point)
c. HCl, HBr, HI,HF (Thermal Stability)
22. Calculate a) molality b) Molarity c) Mole fraction of KI if density of 20 % /(m/m) aqueous
KI is 1.202 g/ml
23. Distinguish between
a. Order and Molecularity
b. Elementary and Complex Reaction
c. First order and Pseudo first order reaction
24.
C6H5OH
Sn/Hcl
Zn/ A
D
ConHNO3/
ConH2SO4
HNO2 /HCl
E
B
Br2
H3O
F
C
25. Draw splitting of d orbital in Tetra hedral Crystal field and define CFSE?
26. Convert
1. Acetone to tertiary butyl alcohol.
www.cpprashanthschemistry.com
Page 2
2.Ethanoic acid to propanoic acid
3. Toluene to benzaldehyde.
27.Calculate the packing efficiency in CCP structure.
28.Write short notes on H2 - O2 Fuel cell
b.The electrical resistance of a column of 0.05 mol /L NaoH solution of diameter 1cm
and length 50 cm is 5.55 X 10 3- Ohm. Calculate its resistivity, Molar conductivity and
Specific Conductivity
(or)
a. Calculate EMF at 298K
E o Cu 2+ /Cu = 0.34 V, Eo Mg 2 + /Mg = -2.36V
(0.0001M)
(o.001 M)
b. Write short notes on Lead Storage battery
29. a. Complete the following chemical reaction
1. F2 +H2O
2. Ca3P2 + H2O
3. O3 + I- +H2O
b. Draw the structure of
XeOF4 , H2SO4
(or)
Give reason
a. NH3 has more Boiling Point than PH3
b. H2O is in liquid state, H2S is in gaseous state
c. S2 in vapour phase is Paramagnetic
Draw structure of
XeO3, H2S2O7
30.1. Give reason
a. Transition metal ions are coloured
b. Actionoid contraction is greater than Lanthanoid contraction
c. Transition metals are good catalyst
3. Complete the following
Cr2O72 - +H+ + CrO4 2_
www.cpprashanthschemistry.com
Page 3
MnO4- + H+ + NO2 –
(or)
2. a . Describe the preparation of KMnO4 from Pyrolusite
b. What is misch metal alloy ? Write its uses
c. What is lanthanoid contraction?
d. MnO4 - +Fe2 + +H+
e. Cr2O7 2- +Sn2+ +H+
www.cpprashanthschemistry.com
Page 4
SAMPLE PAPER -9
SCORING KEY
1. Vitamin A
1
Vitamin K
2. Thermoplastic - Polythene , Polyvinyl chloride
1
3. Vinegar, Sodium benzoate
1
4. 2, 4 – Dimethyl – 3-Oxo Pentanal
1
5. By using depressant (chemical) certain types of ore particles can be prevented from
froth during froth floatation.Ex: NaCN
1
6. Protein synthesis or replication.
1
7. Due to the unequal bombardment of colloidal particles with the dispersion medium1
8. Ferrimagnetic – Fe, Co, Ni, ,CrO2
1
9. For nitration , mixture of ConHNO3 , Con H2SO4 is used . When aniline is treated with
Con H2SO4 it is oxidised to complex compounds due to high electron density on
benzene ring. -NHCOCH3 decreases electron density on benzene
2
10. DNA - Double stranded helical structure
Nitrogen bases A , T, G, & C
1
RNA - Single Stranded
Nitrogen bases A, U, G, C
1
(or)
Helix – peptide chains are right handed screw due to formation of inter H bond
between CO gp of one turn amino acid and NH gp of next turn amino acid . Pleated Peptide
chains are arranged side by side in Zig – Zag with alternate R on same side.
Two neighbouring chains are held by H bond . Sheets are stacked one above the other
like pages of book.
1+1
11. Henry’s law - The solubility of a gas in a solvent is directly propotional to pressure
of the gas at constant temperature.
Aerated soda bottle, Solubility of gas CO2 is increased by kept under high pressure (or) any one
application.
1+1
12.
F Go of Co2 from CO is higher than ZnO from Zn .So CO is not possible. So CO from
C is less than ZnO from Zn. So it is a good reducing agent
2
www.cpprashanthschemistry.com
Page 5
13.PHBV , Nylon2, Nylon 6.
(2)
14.Antiseptics can be applied on living tissues Disinfectant can’t be applied on living tissues
(2)
15..K = 2.303/t log No/N
1
1.15 X 10 -3 - 2.303/t log 10/5
T = 2.303 X 103/ 1.152 log2
= 2.303 X103 X 0.3010/1.15
T= 2 X301 = 0.301 = 602 sec
1
16. Reimer- Tiemann reaction (Phenol to salicylaldehyde)
C6H5 OH
CHCl3
,
NaOH, 340K
o-C6H4 (ONa)CHO
H3O+
o- C6H4 (OH)CHO
,
1
b. Williamson’s synthesis.(Alkoxide to ether)
RONa + RCl
ROR.
2
17.1.Phenol +Br2 (aq)
2,4,6- Tribromo Phenol.
2. C6H5NH2 +C6H5N2cl
18s. 1. HCHO
C6H5N2 C6H4NH2 +HCl
No alpha H atom
CH3 CHO
α-H atom is there so undergoes aldol condensation
2. Phenol - neutral FeCl3 violet coloration
Benzoic acid undergoes NaHCO3 test & forms brisk effervescence.
1
2
1
1
1
1
19. a. Path of light is illuminated by colloidal particles.
b. Coagulation takes place
c.
Deltas are formed.
www.cpprashanthschemistry.com
3
Page 6
20. The compound A is DDT( Di chloro diphenyl trichloro ethane. It causes pollution
Environment should be protected.
1*3=3
21. a. angle Strain is more
b. No2 has odd electron so it gets paired in N2O4
c. N forms p pi –p pi multiple bond but P can’t form p pi –p pi as its atomic orbital is too large
and diffuse to have effective overlapping
1*3=3
(OR)
a. HF<HCL<HBr<HI
b. HCL<HBr<HI<HF
C. HI<HBr<HCL<HF
1*3=3
23. A. Molality = mass of KI / m.mass of KI
= 20/ 166
X
X 1000/ mass of solvent
1000/80
b. Molarity = mass of KI / m.mass of KI
= 20/166
X
1000 / 83.2
= 1.5 mol/kg
1
X 1000/ Volume of Solution
= 1.45M
1
c. X mole fraction
KI = 20/166 =0.120 moles
H20 = 80/18 = 4.44
X of KI = o.120/0.120 + 4.44= 0.026
24. order
1
sum of powers to which concentration terms are raised in
rate law determined experimently
1
Molecularity
sum of the reactant molecules which march collide
to bring about chemical reaction in a balanced equation. Determined theoretically. 1
b)the reaction that takes place in a single step ,the reaction takes place in more than one step.s
www.cpprashanthschemistry.com
Page 7
25. A-benzene, B-Nitrobenzene, C- metabromonitro benzene,
D- C- metabromoaniline E- - metabromobenzenediazonium chloride
F- - metabromophenol
26.CH3-CO-CH3
CH3MgBr,H2O
3
CH3-C(CH3)OH-CH3
CH3COOH to CH3CH2COOH
CH3COOH redn
CH3CH2OHsocl2,Kcn CH3CH2CN
C6H5CH3
Cl2,light C6H5CHCl2
H2O
3
H2O
CH3CH2COOH
C6H5CHO
27. a= 4r/√2 packing efficiency =volume occupied by four sphere/total volume of the unit cell
=4*4 * πr3 *100/ 3*(2√2r)3
=74%
1*3=3
28. A. H2 – O2 Fuel cell
H2 + 4 OH-
4 H2O +4e
O2 + 2H2O+
4OH-
2H2 + O2
2H2O
–
1*2=2
B. Restivity , m, K
R= 1/2 cm
Area = π r2 = 3.14 X (0.5)2
= 0.785 cm2
ῤ = RA/l
= 5.55 x 10 3 X 0.785/50
= 87.135 cm
K = 1/ ῤ
= 1/87.135
www.cpprashanthschemistry.com
Page 8
= 11.48 X 10 -3 scm-1
= 1000 X K/M
= 11.48 X10-3 X 1000/0.05
= 220.65 cm2/mol
1*3=3
(or)
28)
a. E = Eo +o.o59/n log (Cu2+)/(mg2+)
=Eo = 2.71V
E cell = 2.71 – 0.059/2 log (0.001/0.0001)
–
E cell = 2.68 V
1*3=3
b.Anode
Pb+SO4 2-
pbSO4 +2e-
Cathode
pbO2 +SO42- +4H+ +2e29)
pbSO4+ 2 H2O
F2 +H2O
Ca3p2 +H2o
O3 +I- +H2O
1+1
H+F- +O2
Ca (OH)2 +PH3
OH- +I2 +O2
b.structure
1*3=3
2
(or)
a. Intermolecular H bond
b. Intermolceular H bond
c. Unpaired electron
Stucture
1*3=3
1*2=2
30 A. d-d transition
b.Poor shielding of 5f than 4f
c.provides area for reacting and weaken reaction bond & form intermediate with reactant
a. CO2 +Cr3+ + H2O
1*5=5
2+
b. NO3- + Mn + H2O
(or)
a. KOH + MnO2 +O2
K2MnO4 +H2O
1*5=5
www.cpprashanthschemistry.com
Page 9
MnO42MnO4b. 95% Lanthanoid , 5% Iron , S, C, Ca, Al
Uses Lighter flint , bullet
c.
Gradual decrease in ionic radius from La3+ toL u3+
d. Mn2+ + Fe3+ +H2O
e)Sn4+ + Cr3+ +H2O
-------------------------------------------------------------------------------------------------------------------------
www.cpprashanthschemistry.com
Page 10
SAMPLE PAPER -9
Blue Print
S.no
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Unit
Solid state
solution
E.Chemistry
Kinetics
S. Chemistry
Metallurgy
pblock
D block
Coordination
Compds
Org .I
Org .II
Org .III
Org .IV
Biomolecules
Polymer
Che. In every
day life.
SA
1
SA
2
SA
3
3
LA
5
2
1
1
3
3
2
3
3
1
1
1(2)
1(2)
1
1
www.cpprashanthschemistry.com
3
2(2)
2
2
2
2
3
5
5
TOTAL
4
5
5
5
4
3
8
5
3
4
4
6
4
4
3
3
Page 11