Code : 1105/1
SAMPLE QUESTION PAPER
CHEMISTRY (043)
CLASS-XI– (2013-14)
BLUE PRINT
2
3
4
5
6
7
8
9
10
11
12
13
14
Some basic concept of
chemistry
Structure of atom
Classification of
elements and
periodicity in
properties
Chemical bonding and
molecular structure
States of matter; gases
and liquid
Thermodynamics
Equlibrium
Redox reaction
Hydrogen
S-block elements
Some p block elements
Organic chemistry:
some basic principle
and technique
Hydrocarbons
Environmental
chemistry
TOTAL
1(1)
1(1)
Value
based(4mark)
2(1)
3(1)
11
2(1)
3(1)
3(1)
4
3(1)
21
2(1)
1(1)
LA(5 marks)
SAII(3marks)
1
TOTAL
SAI(2marks)
S UNIT
No
Maximum Marks:70
VSA(1 marks)
Time Allowed: 3 Hrs.
4(1)
6(2)
5(1)
1(1)
2(1)
2(1)
16
6(2)
5(1)
6(2)
1(1)
5(5)
18
3(1)
3(1)
10(5) 36(12)
5(1)
4(1)
15(3)
70(26)
VINU . T. V RAO PGT : Chemistry ; K.V DINJAN , ASSAM
Code : 1105/1
KENDRIYA VIDYALAYA SANGATHAN
TINSUKIA REGION
SESSION ENDING EXAMINATION
MAX.MARK-70
CLASS-XI
SUB: CHEMISTRY
TIME: 3 Hrs.
GENERAL INSTRUCTIONS:
* Answer all the questions:
* Questions no.1 to 5 carry one mark each.
* Questions no.6 to 10carry 2 marks each.
* Questions no.11 to 22 carry 3 marks each.
* Questions no.23 carries 4 marks.
* Questions no.24 to 26 carry 5 marks each.
* There is no overall choice. However there is internal choice in one question each of two
mark and three marks questions. All 5 marks questions have internal choice.
* Calculator or any other electronic items are not allowed. However logarithm book may be
used for calculations.
1)
What property of molecules of real gases is indicated by van der Waal’s constant a ?
2)
What is Acid Rain?
3)
Write the correct set of four quantum no for the valence electron of Potassium atom (Z=19)
4)
Write the name of two spin isomer of Hydrogen.
5)
Write the IUPAC name and symbol for the element with atomic no 119.
6)
A sample of drinking water was found to be severely contaminated with chloroform (CHCl3) ,
supposed
to be carcinogenic in nature. The level of contamination was 15 ppm (by mass)
a.
b.
7)
Express this in percent by mass
Determine the molality of chloroform in water sample.
An electron has a speed of 40 ms-1 accurate up to 99.99% what is uncertainty in locating its
position?(Given Me=9.11x10-31kg)
8)
Give correct reason for the following:
VINU . T. V RAO PGT : Chemistry ; K.V DINJAN , ASSAM
Code : 1105/1
a) BF3 has zero dipole moment although the B—F bonds are polar.
b)All carbon to oxygen bonds in CO3-2 are equivalent.
9)
Balance the following redox reaction by ion electron method in basic medium.
MnO4-1 (aq) +I-→ MnO2(s) +I2(s)
10)
Complete the following reactions
a) PbS(s) +H2O2 (aq)→
b) Ca (HCO3)2 +Ca (OH)2→
OR
Account for the following:
a.
b.
11)
Soft water lathers with soap but not hard water.
Temporary hardness of water can be removed by boiling.
Account for the following:
a. Ionisation enthalpy of nitrogen is more than that of Oxygen
b. Acation is always smaller than their parent atom.
c. Noble gases have large positive electron gain enthalpy.
12)
State and explain Hess´s law of constant heat summation? By using this law calculate the
enthalpy change of the following reaction
C (graphite, s) +1/2O2 (g) --------->CO (g);
H=?
By using the following data
13)
C (graphite, s) +O2 (g) ------------->CO2 (g);
H= -393.5 KJ/mol
CO (g) +1/2O2 (g) ----------------->CO2 (g);
H= -283.0KJ/mol?
a).StatePauli,s exclusion Principles
b.) Account for the following:
(i) Chromium has the configuration 3d54S1 and not 3d4 4S2
(ii) Bohr,s orbit are called stationary orbits or states.
14)
Explain the following terms:
a).Photochemical smog
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Code : 1105/1
b). Acid rain
c). Eutrophication.
15)
a). write the molecular configuration of O2+ molecular ion calculate its bond order and predict its
magnetic behavior.
b). What is state of hybridization of nitrogen in NH4+ ion.
16)
a.
b.
c.
Account for the following:
Potassium carbonate can not be prepared by Solvay process.
Beryllium and Magnesium do not give colour to flame.
Alkali metals and alkaline earth metals can not be obtained by chemical reduction.
OR
Write chemical equationsfor the following reactions
a. Sodium metal is dropped in water.
b. Sodium metal is heated in free supply of air.
c. Sodium peroxide is dissolved in water.
17)
a) What would be SI unit for quantity PV2T2/n?
b) Calculate the volume occupied by 8.8 gm of CO2 at 31.10C and 1 bar pressure.
(R=0.083bar LK-1mol-1)
18)
Arrange the following in order of property mentioned against each:
(i)
19)
20)
21)
22)
23.
(CH3)3C , CH3CH2CH (CH3) , CH3CH2CH2CH2 ( Increasing stability order)
(ii)
CH3CH2COOH, (CH3)2CHCOOH and (CH3)3COOH ( Increasing acidic strength)
a. Write the name of Isomerism among the following compounds
CH3-O-CH2CH2CH3& C2H5-O-C2H5
Calcium carbonate react with aqueous HCl to give CaCl2 and CO2 according to reaction:
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
What mass of CaCO3 is required to react completely with 25 ml of 0.75M HCl ?
Write the all reactions involved in the preparation of sodium carbonate from sodium chloride in
Solvay process.
Explain the following with examples (2+1)
a)Electrophiles and Nucleophile
b)Addition reaction
How do you account for the formation of ethane during chlorination of methane? Explain giving
mechanism.
Eisha and Jyoti were preparing for the class test Eisha asked Jyoti, “ we have general gas equation
PV=RT, but on substituting the value we find that PV is almost never equal to RT, it is either less
than or greater than RT. What is the reason? Jyoti said, “ I tell you. The PV=RT equation is based on
VINU . T. V RAO PGT : Chemistry ; K.V DINJAN , ASSAM
Code : 1105/1
certain assumptions which are not always met (faulty assumptions). That is why PV isnot equal toRT
always.”
a.
b.
c.
Write any one faulty assumption we make in the derivation of gas equation?
What is gas equation for n moles of a real gas?
Write a value associated with this question.
a. Write the conjugate acid of CH3OO-(1+2+2)
24)
b. Calculate the pH of a 1x10-8 M solution of HCl.
c. Calculate the solubility of A2X3 in pure water, assuming that neither kind of ions reacts with water.
The solubility product of A2X3, Ksp=1.1x10-23
OR
a.
b.
Write the conjugate acid of NH3.
Assign reason for the following:
(i)
A solution of NH4Cl in water is shows pH less than 7.
(ii)
In qualitative analysis of group III cations, NH4Cl is added before adding NH4OH for testing Fe+3
or Al+3 ions
c.
Consider the reaction:
N2(g) + H2(g)
2NH3 +Heat
Indicate the direction in which the equilibrium will shift when:
(i)
Temperature is increased
(ii)
Pressure is increased
25.
a) Draw the structure of B2H6.
(1+2+2)
b) What happens when
(i)
(ii)
Boric acid is added to water
Aluminium is treated with dilute NaOH
c) Give suitable reason reason for the following:
(i)
(ii)
[SiF6]-2 is known where as [SiCl6]-2 not
In group 14, the tendency for catenation decreases with increasing atomic no
OR
a. Complete the following chemical equation:
∆
(i)
Fe2O3+3CO→
(ii)
CaCO3 + 2HCl→
b.
Write a brief account for the following:
VINU . T. V RAO PGT : Chemistry ; K.V DINJAN , ASSAM
Code : 1105/1
(i)
Diamond is covalent yet it has high melting point.
(ii)
Atomic radius of gallium (135pm) is less than that of Aluminium (143pm).
(iii)
Graphite is a good conductor of electricity but but diamond is insulator
26. a) Explain the following reaction with examples
(1+1+2+1)
i) Wurtz reaction.
ii) Friedal-craft alkylation reaction.
b. An alkene A on ozonolysis gives a mixture of ethanal and pentan-3-one write the structure of
compound A
c. Give a chemical test to distinguish between ethane and ethyne
OR
a. Write the suitable reason for the following:
i)
C-C bond length in benzene ring is 139 pm which is in between C-C
(single bond)154pm and C=C (double bond) 133pm
(i)
Trans – 2-butene has higher melting point than cis – isomer.
b. Give a chemical test to distinguish between but-1-yne and but-2 –yne
c. How will you carry out following conversions :
(i)
Ethene to benzene
(ii)
1-bromo propane to 2-bromo propane
VINU . T. V RAO PGT : Chemistry ; K.V DINJAN , ASSAM
Code : 1105/1
MARKING SCHEME
1.
2.
3.
4.
5.
6.
Force of attraction
Definition
n=4,l=0,m=0,s=+½
ortho and para
Ununennium,Uue
a.Percent by mass=15x102/106
1.5x10-3
1
1
1
1
b.
molality=1.5x10-2/118.5
1/2
1/2
1/2
= 0.000127m
7.
1/2
½
∆X = h/4πmv
6.6x10-34
8.
4x3.14x9.11x10-31x.004
1/2
1.447x10-2m
½+½
a. Due to symmetrical structure, Dipole moments cancel
1
b. Due to hybrid of three resonance structure
1
9. Oxidation half
I-1(aq) →I2 (s)
1/2
MnO4-1 (aq)→ MnO2(s)
Reduction half
1/2
6I-1(aq) + 2MnO4-1 +4H2O(l)→3I2(s) + 2MnO2(s) + 8OH-1
10.
1
a. PbS(s) +H2O2(aq) → PbSO4(s) + 4H2O(l)
1
b. Ca(HCO3)2 + Ca(OH)2 → 2CaCO3(s) + 2 H2O(l)
1
OR
a.
Hard water contain ions of calcium and magnesium due to formation of
1
b.
Due to formation of calcium carbonate and settle down
1
11. a. Due to half filled orbital
1
b. Due to more effective nuclear charge
1
c. due to stable octet
1
scum
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Code : 1105/1
12. Law, adding equation and finding answer(-110.5KJ/mol)
13. a. correct definition
1
b. (i) due to half filled configuration( or more exchange of energy)
(ii) Energy of orbits is fixed
14.
1
1
a. correct definition
1
b correct definition
1
c. correct definition
1
15. a. correct configuration
1
½
BO=Nb-Na/2
BO=2.5
½
Paramagnetic
½
b. SP3
16.
(1+2)
½
a. potassium hydrogen carbonate is too soluble
1
b. due to stable octet high energy required to excite electron
1
c. because they are stronger reducing agents
1
OR
a. 2Na+2H2O →
2NaOH + H2
b. 2Na + O2→ Na2O2
c. Na2O2 +2H2O→ 2NaOH + H2O2
17
1
1
1
a. kg m5sec-2K2mol-1
1
b .PV=nRT
1/2
1XV=8.8X.083X304.1/44
1/2
V=5.048L
18. a.
19.
1
(CH3)3C-< CH3CH2CH-(CH3)< CH3CH2CH2CH2-
b.
(CH3)3COOH
c.
metamerism
<, (CH3)2CHCOOH <CH3CH2COOH
(1+1+1)
25 ml of 0.75M HCL= 1X25X0.75/1000 mole of HCl
1
= 0.01875mol of HCL
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
1
VINU . T. V RAO PGT : Chemistry ; K.V DINJAN , ASSAM
Code : 1105/1
1 mole
2 mole
(100gm)
0.01875 mole of HCl react with with = 100X0.01875/2 = 0.9375 g
20.
2NH3+H2O+CO2→ (NH4)2CO3
(NH4)2CO3+H2O +CO2 →NH4HCO3
NH4HCO3 + NaCl → NH4Cl + NaHCO3
2NaHCO3→ Na2CO3 +CO2 + CO2 + H2O
21.
a
(1)
1/2
1/2
1
1
Correct definition
b.Correct definition
2
1
hƲ
22. Initiation Cl----Cl → 2Cl .free radical
1
Propagation
CH3-H + Cl . →CH3 . +HCl
.
CH3 +Cl-Cl → CH3Cl + Cl.
1
Termination CH3.+ CH3. → CH3-CH3
23. a
1
any one faulty assumption
2
1
2
b. ( P+an /V ) ( V-nb) =nRT
1
c. sharing of ideas/ any other value associated with the situation
24.
a.C H3COOH
b.
1
1
[H+] = 10-7 + 10-8
pH = - log(H+)
pH= 6.79
c.
2
S=(Ksp/Xx.Yy) 1/x+y
S = ( 1.1X10-23 /22x33)1/2+3
1X10-5mol/litre
2
OR
a . N H4+
1
b (i) In hydrolysis of NH4Cl it gives NH4OH( weak base) and HCl (Strong acid) the resultant solution
is acidic so pH less than 7
1
(ii) concentration of OH- fromNH4OH is suppressed because of common ion 1effect thus with
smaller OH- ion concentration only Fe+3 , Al+3 precipitated
C . (i) backward
1
(ii) forward
1
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Code : 1105/1
25. a.correct structure
1
b. (i) B(OH)3 + 2HOH→[B(OH)4]- + H3O+
1
(ii) 2Al(s)+ 2NaOH(aq) +6H2O → 2Na+[Al(OH)4-] (aq) +3H2(g)
c.
1
(i) due to small size of F silicon can accommodate six F atom while size of chlorine is big
silicon cannot accommodate six chlorine atom
1
(ii) from top to bottom atomic size increases the bond strength decrease
1
OR
∆
a.
(i)Fe2O3+3CO → 2Fe + 3CO2
(ii) CaCO3 + 2HCl → CaCl2 + CO2 + H2O
1
1
b. ( i) each carbon atom is attached with with four carbon atom by sp3 hybridisation in
tetrahedral manner
1
(ii) due to d orbital which have poor shielding effects
1
(iii) in graphite each carbon atom is attached with three carbon atom having
sp3hybridisation each carbon atom has one electron free which is
responsible for conductivity
1
26. a.(i) 2R-X +2Na→ R-R + 2NaX
1
(ii) C6H6 +CH3Cl
b.
C6H5CH3 +HCl
CH3-CH2-C=CH-CH3
│
CH2 -CH3
1
1
c. Ethyne gives white ppt with ammonical silver nitrate while ethane do not give test / any
other correct answer
1
OR
a. (i) due to resonance
1
(ii) molecule of trans isomer can fit more tightly into one another
1
b. But-1-yne has acidic hydrogen will give white ppt with ammonical silver nitratewhile but2-yne do not give
1
c.
Red hot(Cu)
(i) CH2=CH2 +Cl2 →CH2Cl-CH2Cl+KOH(alc)→CH≡CH --------> C6H6
1
HBr
(ii) CH3CH2CH2Br +KOH(alc) →CH3CH=CH2 - → CH3-CH-CH3
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Code : 1105/1
│
1
Br
VINU . T. V RAO PGT : Chemistry ; K.V DINJAN , ASSAM