CBSE - 2012 (Pre) Code -B, Chemistry - Solution, Class, CBSE Notes | EduRev

: CBSE - 2012 (Pre) Code -B, Chemistry - Solution, Class, CBSE Notes | EduRev

 Page 1


 Important Instructions
1. The Answer Sheet is inside this test Booklet. When you are directed to open the Test Booklet, take out
the Answer Sheet and fill in the particulars on side-1 and side-2 carefully with blue/black ball point pen
only.
2. The Test is of 3 hours duration and Test Booklet contains 200 questions. Each question carries 4 marks.
For each correct response, the candidate will get 4 marks. For each incorrect response, one mark will
be deducted from the total scores. The maximum marks are 800.
3. Use Blue/Black Ball Point Pen only for writing particulars on this page/marking responses.
4. Rough work is to be done on the space provided for this purpose in the Test Booklet only.
5. On completion of the test, the candidate must handover the Answer Sheet to the invigilator in
the Room/Hall. The candidates are allowed to take away this Test Booklet with them.
6. The CODE for this Booklet is B. Make sure that the CODE printed on Side-2 of the Answer Sheet is the
same as that on this Booklet. In case of discrepancy, the candidate should immediately report the matter
to the Invigilator for replacement of both the Test Booklets and the Answer Sheets.
7. The candidates should ensure that the Answer Sheet is not folded. Do not make any stray marks on the
Answer Sheet. Do not write your roll no. anywhere else except in the specified space in the Test Booklet/
8. Use of white fluid for correction is NOT permissible on the Answer Sheet.
9. Each Candidate must show on demand his/her Admission Card to the Invigilator.
10. No candidate, without special permission of the Superintendent or Invigilator, would leave his/her seat.
11. The candidates should not leave the Examination Hall without handing over their Answer Sheet to the
Invigilator on duty and sign the Attendance Sheet twice. Cases where a candidate has not signed the
Attendance Sheet the second time will be deemed not to have handed over Answer Sheet and dealt with
as an unfair means case.
12. Use of Electronic/Manual Calculator is prohibited.
13. The candidates are governed by all Rules and Regulations of the Board with regard to their conduct in the
Examination Hall. All cases of unfair means will be dealt with as per Rules and Regulations of the Board.
14. No part of the Test Booklet and Answer Sheet shall be detached under any circumstances.
15. The candidates will write the Correct Test Booklet Code as given in the Test Booklet/Answer Sheet in the
Attendance sheet.
Name of the Candidate (in Capital Letters): _________________________________________________
Roll Number : in figure _______________________________________________________________
: in words _______________________________________________________________
Centre of Examination (in Capitals): _______________________________________________________
Candidate’s Signature : ________________________ Invigilator’s Signature _____________________
Fascimile signature stamp of Centre superintendent___________________________________________
Test Booklet Code
B
Page 2


 Important Instructions
1. The Answer Sheet is inside this test Booklet. When you are directed to open the Test Booklet, take out
the Answer Sheet and fill in the particulars on side-1 and side-2 carefully with blue/black ball point pen
only.
2. The Test is of 3 hours duration and Test Booklet contains 200 questions. Each question carries 4 marks.
For each correct response, the candidate will get 4 marks. For each incorrect response, one mark will
be deducted from the total scores. The maximum marks are 800.
3. Use Blue/Black Ball Point Pen only for writing particulars on this page/marking responses.
4. Rough work is to be done on the space provided for this purpose in the Test Booklet only.
5. On completion of the test, the candidate must handover the Answer Sheet to the invigilator in
the Room/Hall. The candidates are allowed to take away this Test Booklet with them.
6. The CODE for this Booklet is B. Make sure that the CODE printed on Side-2 of the Answer Sheet is the
same as that on this Booklet. In case of discrepancy, the candidate should immediately report the matter
to the Invigilator for replacement of both the Test Booklets and the Answer Sheets.
7. The candidates should ensure that the Answer Sheet is not folded. Do not make any stray marks on the
Answer Sheet. Do not write your roll no. anywhere else except in the specified space in the Test Booklet/
8. Use of white fluid for correction is NOT permissible on the Answer Sheet.
9. Each Candidate must show on demand his/her Admission Card to the Invigilator.
10. No candidate, without special permission of the Superintendent or Invigilator, would leave his/her seat.
11. The candidates should not leave the Examination Hall without handing over their Answer Sheet to the
Invigilator on duty and sign the Attendance Sheet twice. Cases where a candidate has not signed the
Attendance Sheet the second time will be deemed not to have handed over Answer Sheet and dealt with
as an unfair means case.
12. Use of Electronic/Manual Calculator is prohibited.
13. The candidates are governed by all Rules and Regulations of the Board with regard to their conduct in the
Examination Hall. All cases of unfair means will be dealt with as per Rules and Regulations of the Board.
14. No part of the Test Booklet and Answer Sheet shall be detached under any circumstances.
15. The candidates will write the Correct Test Booklet Code as given in the Test Booklet/Answer Sheet in the
Attendance sheet.
Name of the Candidate (in Capital Letters): _________________________________________________
Roll Number : in figure _______________________________________________________________
: in words _______________________________________________________________
Centre of Examination (in Capitals): _______________________________________________________
Candidate’s Signature : ________________________ Invigilator’s Signature _____________________
Fascimile signature stamp of Centre superintendent___________________________________________
Test Booklet Code
B
1. CH
3
CHO and C
6
H
5
CH
2
CHO can be distinguished chemically by
(1) Fehling solution test (2) Benedict test
(3) Iodoform test (4) Tollen’s reagent test
Sol: [3] Aldehydes and ketones having 
3
O
||
CH C ? ?
 group give iodoform test.
3 2 3 2
Yellow ppt.
O
||
CH C H 3I 4NaOH CHI HCOONa 3NaI 3H O ? ? ? ? ?? ? ? ? ?
2. p
A
 and p
B
 are the vapour pressure of pure liquid components. A and B, respectively of an ideal binary
solution. If x represents the mole fraction of component A, the total pressure of the solution will be
(1) p + x (p – p ) (2) p + x (p – p ) (3) p + x (p – p ) (4) p + x (p – p )
Sol: [1] p
Total
 = p
A
 ? x
A
 + p
B 
? x
B
x + x = 1
x = 1 – x
p = p  x + p (1 – x )
3. Which one of the following is not a condensation polymer?
(1) Neoprene (2) Melamine (3) Glyptal (4) Dacron
Sol: [1] Addition polymer of chloroprene is neoprene
C H
2
CH
2
Cl
Chloroprene is 
4. A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is 408 pm. The diameter
of the metal atom is :
(1) 204 pm (2) 288 pm (3) 408 pm (4) 144 pm
Sol: [2]
a 408
2a 4r 2 288pm
1.414 2
? ? ? ? ? ?
5. Equimolar solutions of the following substances were prepared separately. Which one of these will
record the highest pH value?
(1) BeCl
2
(2) BaCl
2
(3) AlCl
3
(4) LiCl
Sol: [2] Salt of strong acid and strong base
6. In the following reaction:
C CH C H
3
CH
3
CH
3
CH
2
2
H O / H
Major product Minor product
A B
?
? ? ? ? ? ?
CBSE - 2012 (Pre)
CHEMISTRY CODE – B
Page 3


 Important Instructions
1. The Answer Sheet is inside this test Booklet. When you are directed to open the Test Booklet, take out
the Answer Sheet and fill in the particulars on side-1 and side-2 carefully with blue/black ball point pen
only.
2. The Test is of 3 hours duration and Test Booklet contains 200 questions. Each question carries 4 marks.
For each correct response, the candidate will get 4 marks. For each incorrect response, one mark will
be deducted from the total scores. The maximum marks are 800.
3. Use Blue/Black Ball Point Pen only for writing particulars on this page/marking responses.
4. Rough work is to be done on the space provided for this purpose in the Test Booklet only.
5. On completion of the test, the candidate must handover the Answer Sheet to the invigilator in
the Room/Hall. The candidates are allowed to take away this Test Booklet with them.
6. The CODE for this Booklet is B. Make sure that the CODE printed on Side-2 of the Answer Sheet is the
same as that on this Booklet. In case of discrepancy, the candidate should immediately report the matter
to the Invigilator for replacement of both the Test Booklets and the Answer Sheets.
7. The candidates should ensure that the Answer Sheet is not folded. Do not make any stray marks on the
Answer Sheet. Do not write your roll no. anywhere else except in the specified space in the Test Booklet/
8. Use of white fluid for correction is NOT permissible on the Answer Sheet.
9. Each Candidate must show on demand his/her Admission Card to the Invigilator.
10. No candidate, without special permission of the Superintendent or Invigilator, would leave his/her seat.
11. The candidates should not leave the Examination Hall without handing over their Answer Sheet to the
Invigilator on duty and sign the Attendance Sheet twice. Cases where a candidate has not signed the
Attendance Sheet the second time will be deemed not to have handed over Answer Sheet and dealt with
as an unfair means case.
12. Use of Electronic/Manual Calculator is prohibited.
13. The candidates are governed by all Rules and Regulations of the Board with regard to their conduct in the
Examination Hall. All cases of unfair means will be dealt with as per Rules and Regulations of the Board.
14. No part of the Test Booklet and Answer Sheet shall be detached under any circumstances.
15. The candidates will write the Correct Test Booklet Code as given in the Test Booklet/Answer Sheet in the
Attendance sheet.
Name of the Candidate (in Capital Letters): _________________________________________________
Roll Number : in figure _______________________________________________________________
: in words _______________________________________________________________
Centre of Examination (in Capitals): _______________________________________________________
Candidate’s Signature : ________________________ Invigilator’s Signature _____________________
Fascimile signature stamp of Centre superintendent___________________________________________
Test Booklet Code
B
1. CH
3
CHO and C
6
H
5
CH
2
CHO can be distinguished chemically by
(1) Fehling solution test (2) Benedict test
(3) Iodoform test (4) Tollen’s reagent test
Sol: [3] Aldehydes and ketones having 
3
O
||
CH C ? ?
 group give iodoform test.
3 2 3 2
Yellow ppt.
O
||
CH C H 3I 4NaOH CHI HCOONa 3NaI 3H O ? ? ? ? ?? ? ? ? ?
2. p
A
 and p
B
 are the vapour pressure of pure liquid components. A and B, respectively of an ideal binary
solution. If x represents the mole fraction of component A, the total pressure of the solution will be
(1) p + x (p – p ) (2) p + x (p – p ) (3) p + x (p – p ) (4) p + x (p – p )
Sol: [1] p
Total
 = p
A
 ? x
A
 + p
B 
? x
B
x + x = 1
x = 1 – x
p = p  x + p (1 – x )
3. Which one of the following is not a condensation polymer?
(1) Neoprene (2) Melamine (3) Glyptal (4) Dacron
Sol: [1] Addition polymer of chloroprene is neoprene
C H
2
CH
2
Cl
Chloroprene is 
4. A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is 408 pm. The diameter
of the metal atom is :
(1) 204 pm (2) 288 pm (3) 408 pm (4) 144 pm
Sol: [2]
a 408
2a 4r 2 288pm
1.414 2
? ? ? ? ? ?
5. Equimolar solutions of the following substances were prepared separately. Which one of these will
record the highest pH value?
(1) BeCl
2
(2) BaCl
2
(3) AlCl
3
(4) LiCl
Sol: [2] Salt of strong acid and strong base
6. In the following reaction:
C CH C H
3
CH
3
CH
3
CH
2
2
H O / H
Major product Minor product
A B
?
? ? ? ? ? ?
CBSE - 2012 (Pre)
CHEMISTRY CODE – B
CBSE-2012 (Pre) Chemistry
H 
The major product is:
(1)
C CH
2
C H
3
CH
3
CH
3
CH
2
OH
(2)
C C H C H
3
CH
3
OH
CH
3
CH
3
(3)
C CH
2
CH
2
CH
3
OH
CH
3
O H
(4)
C C H C H
3
CH
3
CH
3
OH
CH
3
Sol: [2]
C H
3
CH
3
CH
3
CH
2
H
?
?? ?
CH
+
C H
3
CH
3
CH
3
CH
3
1,2 alkyl
shift
?
? ? ? ? ? C
+
C H
3
C H
3
CH
3
CH
3
H O H ? ?
?? ? ? C H
3
O
CH
3
CH
3
CH
3
H H
7. The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at
0°C
(1) 0.526 cal/(mol K) (2) 10.52 cal / (mol K)
(3) 21.04 cal / (mol K) (4) 5.260 cal/(mol K)
Sol: [4]
3
f
fusion
H 1.435 10
S 5.256 cal / molK
T 273
? ?
? ? ? ?
8. Limiting molar conductivity of NH
4
OH (i.e.
m 4
(NH OH) ? ) is equal to:
(1)
m 4 m m
(NH Cl) (NaOH) (NaCl) ? ? ? ? ? (2)
m 4 m m
(NH Cl) (NaCl) (NaOH) ? ? ? ? ?
(3)
m m m 4
(NaOH) (NaCl) (NH Cl) ? ? ? ? ? (4)
m 4 m 4 m
(NH OH) (NH Cl) (HCl) ? ? ? ? ?
Sol: [1]
0 0 0
m 4 m m
(NH Cl) (NaOH) (NaCl) ? ? ? ? ?
Self explained
9. Which one of the following is a mineral of iron?
(1) Magnetite (2) Malachite (3) Cassiterite (4) Pyrolusite
Sol: [1] Magnetite (Fe
3
O
4
)
10. In Freundlich Adsorption isotherm, the value of 1/n is:
(1) 1 in case of chemisorption (2) between 0 and 1 in all cases
(3) between 2 and 4 in all cases (4) 1 in case of physical adsorption
Sol: [2]
1/ n
x
Kp
m
?
Page 4


 Important Instructions
1. The Answer Sheet is inside this test Booklet. When you are directed to open the Test Booklet, take out
the Answer Sheet and fill in the particulars on side-1 and side-2 carefully with blue/black ball point pen
only.
2. The Test is of 3 hours duration and Test Booklet contains 200 questions. Each question carries 4 marks.
For each correct response, the candidate will get 4 marks. For each incorrect response, one mark will
be deducted from the total scores. The maximum marks are 800.
3. Use Blue/Black Ball Point Pen only for writing particulars on this page/marking responses.
4. Rough work is to be done on the space provided for this purpose in the Test Booklet only.
5. On completion of the test, the candidate must handover the Answer Sheet to the invigilator in
the Room/Hall. The candidates are allowed to take away this Test Booklet with them.
6. The CODE for this Booklet is B. Make sure that the CODE printed on Side-2 of the Answer Sheet is the
same as that on this Booklet. In case of discrepancy, the candidate should immediately report the matter
to the Invigilator for replacement of both the Test Booklets and the Answer Sheets.
7. The candidates should ensure that the Answer Sheet is not folded. Do not make any stray marks on the
Answer Sheet. Do not write your roll no. anywhere else except in the specified space in the Test Booklet/
8. Use of white fluid for correction is NOT permissible on the Answer Sheet.
9. Each Candidate must show on demand his/her Admission Card to the Invigilator.
10. No candidate, without special permission of the Superintendent or Invigilator, would leave his/her seat.
11. The candidates should not leave the Examination Hall without handing over their Answer Sheet to the
Invigilator on duty and sign the Attendance Sheet twice. Cases where a candidate has not signed the
Attendance Sheet the second time will be deemed not to have handed over Answer Sheet and dealt with
as an unfair means case.
12. Use of Electronic/Manual Calculator is prohibited.
13. The candidates are governed by all Rules and Regulations of the Board with regard to their conduct in the
Examination Hall. All cases of unfair means will be dealt with as per Rules and Regulations of the Board.
14. No part of the Test Booklet and Answer Sheet shall be detached under any circumstances.
15. The candidates will write the Correct Test Booklet Code as given in the Test Booklet/Answer Sheet in the
Attendance sheet.
Name of the Candidate (in Capital Letters): _________________________________________________
Roll Number : in figure _______________________________________________________________
: in words _______________________________________________________________
Centre of Examination (in Capitals): _______________________________________________________
Candidate’s Signature : ________________________ Invigilator’s Signature _____________________
Fascimile signature stamp of Centre superintendent___________________________________________
Test Booklet Code
B
1. CH
3
CHO and C
6
H
5
CH
2
CHO can be distinguished chemically by
(1) Fehling solution test (2) Benedict test
(3) Iodoform test (4) Tollen’s reagent test
Sol: [3] Aldehydes and ketones having 
3
O
||
CH C ? ?
 group give iodoform test.
3 2 3 2
Yellow ppt.
O
||
CH C H 3I 4NaOH CHI HCOONa 3NaI 3H O ? ? ? ? ?? ? ? ? ?
2. p
A
 and p
B
 are the vapour pressure of pure liquid components. A and B, respectively of an ideal binary
solution. If x represents the mole fraction of component A, the total pressure of the solution will be
(1) p + x (p – p ) (2) p + x (p – p ) (3) p + x (p – p ) (4) p + x (p – p )
Sol: [1] p
Total
 = p
A
 ? x
A
 + p
B 
? x
B
x + x = 1
x = 1 – x
p = p  x + p (1 – x )
3. Which one of the following is not a condensation polymer?
(1) Neoprene (2) Melamine (3) Glyptal (4) Dacron
Sol: [1] Addition polymer of chloroprene is neoprene
C H
2
CH
2
Cl
Chloroprene is 
4. A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is 408 pm. The diameter
of the metal atom is :
(1) 204 pm (2) 288 pm (3) 408 pm (4) 144 pm
Sol: [2]
a 408
2a 4r 2 288pm
1.414 2
? ? ? ? ? ?
5. Equimolar solutions of the following substances were prepared separately. Which one of these will
record the highest pH value?
(1) BeCl
2
(2) BaCl
2
(3) AlCl
3
(4) LiCl
Sol: [2] Salt of strong acid and strong base
6. In the following reaction:
C CH C H
3
CH
3
CH
3
CH
2
2
H O / H
Major product Minor product
A B
?
? ? ? ? ? ?
CBSE - 2012 (Pre)
CHEMISTRY CODE – B
CBSE-2012 (Pre) Chemistry
H 
The major product is:
(1)
C CH
2
C H
3
CH
3
CH
3
CH
2
OH
(2)
C C H C H
3
CH
3
OH
CH
3
CH
3
(3)
C CH
2
CH
2
CH
3
OH
CH
3
O H
(4)
C C H C H
3
CH
3
CH
3
OH
CH
3
Sol: [2]
C H
3
CH
3
CH
3
CH
2
H
?
?? ?
CH
+
C H
3
CH
3
CH
3
CH
3
1,2 alkyl
shift
?
? ? ? ? ? C
+
C H
3
C H
3
CH
3
CH
3
H O H ? ?
?? ? ? C H
3
O
CH
3
CH
3
CH
3
H H
7. The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at
0°C
(1) 0.526 cal/(mol K) (2) 10.52 cal / (mol K)
(3) 21.04 cal / (mol K) (4) 5.260 cal/(mol K)
Sol: [4]
3
f
fusion
H 1.435 10
S 5.256 cal / molK
T 273
? ?
? ? ? ?
8. Limiting molar conductivity of NH
4
OH (i.e.
m 4
(NH OH) ? ) is equal to:
(1)
m 4 m m
(NH Cl) (NaOH) (NaCl) ? ? ? ? ? (2)
m 4 m m
(NH Cl) (NaCl) (NaOH) ? ? ? ? ?
(3)
m m m 4
(NaOH) (NaCl) (NH Cl) ? ? ? ? ? (4)
m 4 m 4 m
(NH OH) (NH Cl) (HCl) ? ? ? ? ?
Sol: [1]
0 0 0
m 4 m m
(NH Cl) (NaOH) (NaCl) ? ? ? ? ?
Self explained
9. Which one of the following is a mineral of iron?
(1) Magnetite (2) Malachite (3) Cassiterite (4) Pyrolusite
Sol: [1] Magnetite (Fe
3
O
4
)
10. In Freundlich Adsorption isotherm, the value of 1/n is:
(1) 1 in case of chemisorption (2) between 0 and 1 in all cases
(3) between 2 and 4 in all cases (4) 1 in case of physical adsorption
Sol: [2]
1/ n
x
Kp
m
?
CBSE-2012 (Pre) Chemistry
11. Identify the alloy containing a non-metal as a constituent in it.
(1) Bronze (2) Invar (3) Steel (4) Bell metal
Sol: [3] In steel, C is also present
12. Buffer solutions have constant acidity and alkalinity because:
(1) they have fixed value of pH
(2) these give unionised acid or base on reaction with added acid or alkali
(3) acids and alkalies in these solutions are shielded from attack by other ions
(4) they have large excess of H
+
 or OH
–
 ions
Sol: [2] Self explanatory
13. Which one of the following pairs is isostructural (i.e. having the same shape and hybridization)?
(1)
4 4
[BF and NH ]
? ?
(2)
3 3
[BCl and BaCl ] (3)
3 3
[NH and NO ]
?
(4) [NF
3
 and BF
3
]
Sol: [1] In both the compounds, central atom is sp
3
 hybridized and structure is tetrahedral.
14. pH of a saturated solution of Ba(OH)
2
 is 12. The value of solubility product (K
sp
) of Ba(OH)
2
 is
(1) 5.0 × 10
–6
(2) 3.3 × 10
–7
(3) 5.0 × 10
–7
(4) 4.0 × 10
–6
Sol: [3] pH = 12
pOH = 2 ? [OH
–
] = 10
–2
2
2
Ba(OH) Ba 2OH
? ?
?
? ? ?
? ? ?
? ?2x = 10
–2
x 2x ? ?x = 5 × 10
–3
K
sp
= x (2x)
2
= 5 × 10
-3
× (10
–2
)
2
= 5 × 10
–7
15. 50 mL of each gas A and of gas B takes 150 and 200 seconds respectively for effusing through a pin
hole under the similar conditions. If molecular mass of gas B is 36, the molecular mass of gas A will be
(1) 64 (2) 96 (3) 128 (4) 32
Sol: [4] However question is wrong.
16. The protecting power of lyophilic colloidal sol is expressed in terms of
(1) Oxidation number (2) Coagulation value
(3) Gold number (4) Critical miscelle concentration
Sol: [3] Factual
17. Deficiency of vitamin B
1
 causes the disease
(1) Sterility (2) Convulsions (3) Beri-Beri (4) Cheilosis
Sol: [3] Factual
18. Acetone is treated with excess of ethanol in the presence of hydrochloric acid. The product obtained is:
(1)
C
O C H
3
O C H
3
C
2
H
5
C
2
H
5
(2)
C H
3
CH
2
CH
2
C
CH
3
O
(3)
C H
3
CH
2
CH
2
C
CH
2
O
CH
2
CH
3
(4)
C
OH C H
3
O C H
3
C
2
H
5
Sol: [1]
Page 5


 Important Instructions
1. The Answer Sheet is inside this test Booklet. When you are directed to open the Test Booklet, take out
the Answer Sheet and fill in the particulars on side-1 and side-2 carefully with blue/black ball point pen
only.
2. The Test is of 3 hours duration and Test Booklet contains 200 questions. Each question carries 4 marks.
For each correct response, the candidate will get 4 marks. For each incorrect response, one mark will
be deducted from the total scores. The maximum marks are 800.
3. Use Blue/Black Ball Point Pen only for writing particulars on this page/marking responses.
4. Rough work is to be done on the space provided for this purpose in the Test Booklet only.
5. On completion of the test, the candidate must handover the Answer Sheet to the invigilator in
the Room/Hall. The candidates are allowed to take away this Test Booklet with them.
6. The CODE for this Booklet is B. Make sure that the CODE printed on Side-2 of the Answer Sheet is the
same as that on this Booklet. In case of discrepancy, the candidate should immediately report the matter
to the Invigilator for replacement of both the Test Booklets and the Answer Sheets.
7. The candidates should ensure that the Answer Sheet is not folded. Do not make any stray marks on the
Answer Sheet. Do not write your roll no. anywhere else except in the specified space in the Test Booklet/
8. Use of white fluid for correction is NOT permissible on the Answer Sheet.
9. Each Candidate must show on demand his/her Admission Card to the Invigilator.
10. No candidate, without special permission of the Superintendent or Invigilator, would leave his/her seat.
11. The candidates should not leave the Examination Hall without handing over their Answer Sheet to the
Invigilator on duty and sign the Attendance Sheet twice. Cases where a candidate has not signed the
Attendance Sheet the second time will be deemed not to have handed over Answer Sheet and dealt with
as an unfair means case.
12. Use of Electronic/Manual Calculator is prohibited.
13. The candidates are governed by all Rules and Regulations of the Board with regard to their conduct in the
Examination Hall. All cases of unfair means will be dealt with as per Rules and Regulations of the Board.
14. No part of the Test Booklet and Answer Sheet shall be detached under any circumstances.
15. The candidates will write the Correct Test Booklet Code as given in the Test Booklet/Answer Sheet in the
Attendance sheet.
Name of the Candidate (in Capital Letters): _________________________________________________
Roll Number : in figure _______________________________________________________________
: in words _______________________________________________________________
Centre of Examination (in Capitals): _______________________________________________________
Candidate’s Signature : ________________________ Invigilator’s Signature _____________________
Fascimile signature stamp of Centre superintendent___________________________________________
Test Booklet Code
B
1. CH
3
CHO and C
6
H
5
CH
2
CHO can be distinguished chemically by
(1) Fehling solution test (2) Benedict test
(3) Iodoform test (4) Tollen’s reagent test
Sol: [3] Aldehydes and ketones having 
3
O
||
CH C ? ?
 group give iodoform test.
3 2 3 2
Yellow ppt.
O
||
CH C H 3I 4NaOH CHI HCOONa 3NaI 3H O ? ? ? ? ?? ? ? ? ?
2. p
A
 and p
B
 are the vapour pressure of pure liquid components. A and B, respectively of an ideal binary
solution. If x represents the mole fraction of component A, the total pressure of the solution will be
(1) p + x (p – p ) (2) p + x (p – p ) (3) p + x (p – p ) (4) p + x (p – p )
Sol: [1] p
Total
 = p
A
 ? x
A
 + p
B 
? x
B
x + x = 1
x = 1 – x
p = p  x + p (1 – x )
3. Which one of the following is not a condensation polymer?
(1) Neoprene (2) Melamine (3) Glyptal (4) Dacron
Sol: [1] Addition polymer of chloroprene is neoprene
C H
2
CH
2
Cl
Chloroprene is 
4. A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is 408 pm. The diameter
of the metal atom is :
(1) 204 pm (2) 288 pm (3) 408 pm (4) 144 pm
Sol: [2]
a 408
2a 4r 2 288pm
1.414 2
? ? ? ? ? ?
5. Equimolar solutions of the following substances were prepared separately. Which one of these will
record the highest pH value?
(1) BeCl
2
(2) BaCl
2
(3) AlCl
3
(4) LiCl
Sol: [2] Salt of strong acid and strong base
6. In the following reaction:
C CH C H
3
CH
3
CH
3
CH
2
2
H O / H
Major product Minor product
A B
?
? ? ? ? ? ?
CBSE - 2012 (Pre)
CHEMISTRY CODE – B
CBSE-2012 (Pre) Chemistry
H 
The major product is:
(1)
C CH
2
C H
3
CH
3
CH
3
CH
2
OH
(2)
C C H C H
3
CH
3
OH
CH
3
CH
3
(3)
C CH
2
CH
2
CH
3
OH
CH
3
O H
(4)
C C H C H
3
CH
3
CH
3
OH
CH
3
Sol: [2]
C H
3
CH
3
CH
3
CH
2
H
?
?? ?
CH
+
C H
3
CH
3
CH
3
CH
3
1,2 alkyl
shift
?
? ? ? ? ? C
+
C H
3
C H
3
CH
3
CH
3
H O H ? ?
?? ? ? C H
3
O
CH
3
CH
3
CH
3
H H
7. The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at
0°C
(1) 0.526 cal/(mol K) (2) 10.52 cal / (mol K)
(3) 21.04 cal / (mol K) (4) 5.260 cal/(mol K)
Sol: [4]
3
f
fusion
H 1.435 10
S 5.256 cal / molK
T 273
? ?
? ? ? ?
8. Limiting molar conductivity of NH
4
OH (i.e.
m 4
(NH OH) ? ) is equal to:
(1)
m 4 m m
(NH Cl) (NaOH) (NaCl) ? ? ? ? ? (2)
m 4 m m
(NH Cl) (NaCl) (NaOH) ? ? ? ? ?
(3)
m m m 4
(NaOH) (NaCl) (NH Cl) ? ? ? ? ? (4)
m 4 m 4 m
(NH OH) (NH Cl) (HCl) ? ? ? ? ?
Sol: [1]
0 0 0
m 4 m m
(NH Cl) (NaOH) (NaCl) ? ? ? ? ?
Self explained
9. Which one of the following is a mineral of iron?
(1) Magnetite (2) Malachite (3) Cassiterite (4) Pyrolusite
Sol: [1] Magnetite (Fe
3
O
4
)
10. In Freundlich Adsorption isotherm, the value of 1/n is:
(1) 1 in case of chemisorption (2) between 0 and 1 in all cases
(3) between 2 and 4 in all cases (4) 1 in case of physical adsorption
Sol: [2]
1/ n
x
Kp
m
?
CBSE-2012 (Pre) Chemistry
11. Identify the alloy containing a non-metal as a constituent in it.
(1) Bronze (2) Invar (3) Steel (4) Bell metal
Sol: [3] In steel, C is also present
12. Buffer solutions have constant acidity and alkalinity because:
(1) they have fixed value of pH
(2) these give unionised acid or base on reaction with added acid or alkali
(3) acids and alkalies in these solutions are shielded from attack by other ions
(4) they have large excess of H
+
 or OH
–
 ions
Sol: [2] Self explanatory
13. Which one of the following pairs is isostructural (i.e. having the same shape and hybridization)?
(1)
4 4
[BF and NH ]
? ?
(2)
3 3
[BCl and BaCl ] (3)
3 3
[NH and NO ]
?
(4) [NF
3
 and BF
3
]
Sol: [1] In both the compounds, central atom is sp
3
 hybridized and structure is tetrahedral.
14. pH of a saturated solution of Ba(OH)
2
 is 12. The value of solubility product (K
sp
) of Ba(OH)
2
 is
(1) 5.0 × 10
–6
(2) 3.3 × 10
–7
(3) 5.0 × 10
–7
(4) 4.0 × 10
–6
Sol: [3] pH = 12
pOH = 2 ? [OH
–
] = 10
–2
2
2
Ba(OH) Ba 2OH
? ?
?
? ? ?
? ? ?
? ?2x = 10
–2
x 2x ? ?x = 5 × 10
–3
K
sp
= x (2x)
2
= 5 × 10
-3
× (10
–2
)
2
= 5 × 10
–7
15. 50 mL of each gas A and of gas B takes 150 and 200 seconds respectively for effusing through a pin
hole under the similar conditions. If molecular mass of gas B is 36, the molecular mass of gas A will be
(1) 64 (2) 96 (3) 128 (4) 32
Sol: [4] However question is wrong.
16. The protecting power of lyophilic colloidal sol is expressed in terms of
(1) Oxidation number (2) Coagulation value
(3) Gold number (4) Critical miscelle concentration
Sol: [3] Factual
17. Deficiency of vitamin B
1
 causes the disease
(1) Sterility (2) Convulsions (3) Beri-Beri (4) Cheilosis
Sol: [3] Factual
18. Acetone is treated with excess of ethanol in the presence of hydrochloric acid. The product obtained is:
(1)
C
O C H
3
O C H
3
C
2
H
5
C
2
H
5
(2)
C H
3
CH
2
CH
2
C
CH
3
O
(3)
C H
3
CH
2
CH
2
C
CH
2
O
CH
2
CH
3
(4)
C
OH C H
3
O C H
3
C
2
H
5
Sol: [1]
CBSE-2012 (Pre) Chemistry
19. The ease of adsorption of the hydrated alkali metal ions on an ion-exchange resins follows the order:
(1) Na
+
 < Li
+
 < K
+ 
< Rb
+
(2) Li
+
 < K
+
 < Na
+
 < Rb
+
(3) Rb
+
 < K
+
 < Na
+
 < Li
+
(4) K
+
 < Na
+
 < Rb
+
 < Li
+
Sol: [3] Greater the size of the hydrated ion, more will be the surface area and more will be its ease of
adsorption.
20. Which one of the following statements is incorrect about enzyme catalysis?
(1) Enzymes are least reactive at optimum temperature
(2) Enzymes are mostly proteinous in nature
(3) Enzyme action is specific
(4) Enzymes are denaturated by ultraviolet rays and at high temperature
Sol: [1] Enzyme is most active at optimum temperature and pH
21. In which of the following compounds, nitrogen exhibits highest oxidation state?
(1) NH
2
OH (2) N
2
H
4
(3) NH
3
(4) N
3
H
Sol: [4] Oxidation state of N is N
3
H = –1/3
22. Bond order of 1.5 is shown by:
(1) O
2
(2)
2
O
?
(3)
2
O
?
(4)
2
2
O
?
Sol: [3] Bond Order =
b a
1 1
(N N ) (10 7) 1.5
2 2
? ? ? ?
23. Maximum number of electrons in a subshell with l = 3 and n = 4 is:
(1) 12 (2) 14 (3) 16 (4) 10
Sol: [2] i.e. 4f maximum number of electrons that can be accommodated in f-subshell = 14
24. The correct set of four quantum numbers for the valence electron of rubidium atom (Z = 37) is
(1) 5, 1, 0, +1/2 (2) 5, 1, 1, +1/2 (3) 6, 0, 0, +1/2 (4) 5, 0, 0, +1/2
Sol: [4] i.e. [Kr]5s
1
 so n = 5, l = 0, m = 0, s = +1/2
25. In a reaction, A + B ? ? Product, rate is doubled when the concentration of B is doubled, and rate
increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate
law for the reaction can be written as:
(1) Rate = k[A]
2
 [B] (2) Rate = k[A] [B]
2
(3) Rate = k[A]
2
 [B]
2
(4) Rate = k[A] [B]
Sol: [1] A + B ? ?Product
x y
1
r [A] [B] ?
x y x y y
2 1
r [A] [2B] 2r 2 [A] [B] 2 2 y 1 ? ? ? ? ? ? ? ?
x y x y
3 1
r [2A] [2B] 8r 8 [A] [B] ? ? ? ?
= 2
x
 × 2
y
 = 2
3
 = 2
x
 = 2
2
Rate = k [A]
2
 [B]
26. A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the reaction which
element undergoes maximum change in the oxidation number?
(1) C (2) S (3) H (4) Cl
Sol: [4]
3
ClO
?
 changes to Cl
–
5 1
Cl Cl
? ?
? ? ?
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