CBSE Board Paper 2020 (Marking Scheme and Solutions) | Chemistry Class 12 - NEET PDF Download

 Page 1


General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. To 
avoid mistakes, it is requested that before starting evaluation, you must read and understand 
the spot evaluation guidelines carefully. Evaluation is a 10-12 days mission for all of us. 
Hence, it is necessary that you put in your best efforts in this process. 
2. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be 
done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, answers 
which are based on latest information or knowledge and/or are innovative, they may 
be assessed for their correctness otherwise and marks be awarded to them.  
3. The Head-Examiner must go through the first five answer books evaluated by each evaluator 
on the first day, to ensure that evaluation has been carried out as per the instructions given 
in the Marking Scheme. The remaining answer books meant for evaluation shall be given 
only after ensuring that there is no significant variation in the marking of individual evaluators. 
4. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X”be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
5. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totaled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
6. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
7. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
8. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
10. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours 
every day and evaluate 20 answer books per day in main subjects and 25 answer books per 
day in other subjects (Details are given in Spot Guidelines). 
11. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past:- 
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior School Certificate Examination-2020 
Marking Scheme – CHEMISTRY 
(SUBJECT CODE -043) (PAPER CODE – 56/1/1) 
9. A full scale of marks 0-70 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
Page 2


General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. To 
avoid mistakes, it is requested that before starting evaluation, you must read and understand 
the spot evaluation guidelines carefully. Evaluation is a 10-12 days mission for all of us. 
Hence, it is necessary that you put in your best efforts in this process. 
2. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be 
done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, answers 
which are based on latest information or knowledge and/or are innovative, they may 
be assessed for their correctness otherwise and marks be awarded to them.  
3. The Head-Examiner must go through the first five answer books evaluated by each evaluator 
on the first day, to ensure that evaluation has been carried out as per the instructions given 
in the Marking Scheme. The remaining answer books meant for evaluation shall be given 
only after ensuring that there is no significant variation in the marking of individual evaluators. 
4. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X”be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
5. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totaled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
6. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
7. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
8. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
10. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours 
every day and evaluate 20 answer books per day in main subjects and 25 answer books per 
day in other subjects (Details are given in Spot Guidelines). 
11. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past:- 
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior School Certificate Examination-2020 
Marking Scheme – CHEMISTRY 
(SUBJECT CODE -043) (PAPER CODE – 56/1/1) 
9. A full scale of marks 0-70 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
12. While evaluating the answer books if the answer is found to be totally incorrect, it should be 
marked as cross (X) and awarded zero (0)Marks. 
  
13. Any unassessed portion, non-carrying over of marks to the title page, or totaling error 
detected by the candidate shall damage the prestige of all the personnel engaged in the 
evaluation work as also of the Board. Hence, in order to uphold the prestige of all concerned, 
it is again reiterated that the instructions be followed meticulously and judiciously. 
 
14. The Examiners should acquaint themselves with the guidelines given in the Guidelines for 
spot Evaluation before starting the actual evaluation. 
 
15. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to 
the title page, correctly totaled and written in figures and words. 
 
16. The Board permits candidates to obtain photocopy of the Answer Book on request in an RTI 
application and also separately as a part of the re-evaluation process on payment of the 
processing charges.  
 
 
56/1/1 – Set  
MARKING SCHEME 
Sr. SECONDARY SCHOOL EXAMINATION, 2020 
Subject: CHEMISTRY 
Q.No. Expected Answer / Value Points 
Distribut
ion of 
Marks 
SECTION - A 
1. Racemic Mixture 1 
2. Polarimeter  1 
3. Pent-2-ene / CH
3
CH=CHCH
2
CH
3
 1 
4. Antiseptic 1 
5. CH
3
I + C
6
H
5
OH 1 
6. A 1 
7. Zn 1 
8. No 1 
9. CH
2
=CH-Cl 1 
10. Branched hydrocarbon part 1 
11. B 1 
12. D 1 
13. C 1 
14. C 1 
15. A 1 
16. iii 1 
17. ii 1 
18. i 1 
19. ii 1 
20. i 1 
  
Page 3


General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. To 
avoid mistakes, it is requested that before starting evaluation, you must read and understand 
the spot evaluation guidelines carefully. Evaluation is a 10-12 days mission for all of us. 
Hence, it is necessary that you put in your best efforts in this process. 
2. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be 
done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, answers 
which are based on latest information or knowledge and/or are innovative, they may 
be assessed for their correctness otherwise and marks be awarded to them.  
3. The Head-Examiner must go through the first five answer books evaluated by each evaluator 
on the first day, to ensure that evaluation has been carried out as per the instructions given 
in the Marking Scheme. The remaining answer books meant for evaluation shall be given 
only after ensuring that there is no significant variation in the marking of individual evaluators. 
4. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X”be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
5. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totaled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
6. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
7. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
8. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
10. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours 
every day and evaluate 20 answer books per day in main subjects and 25 answer books per 
day in other subjects (Details are given in Spot Guidelines). 
11. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past:- 
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior School Certificate Examination-2020 
Marking Scheme – CHEMISTRY 
(SUBJECT CODE -043) (PAPER CODE – 56/1/1) 
9. A full scale of marks 0-70 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
12. While evaluating the answer books if the answer is found to be totally incorrect, it should be 
marked as cross (X) and awarded zero (0)Marks. 
  
13. Any unassessed portion, non-carrying over of marks to the title page, or totaling error 
detected by the candidate shall damage the prestige of all the personnel engaged in the 
evaluation work as also of the Board. Hence, in order to uphold the prestige of all concerned, 
it is again reiterated that the instructions be followed meticulously and judiciously. 
 
14. The Examiners should acquaint themselves with the guidelines given in the Guidelines for 
spot Evaluation before starting the actual evaluation. 
 
15. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to 
the title page, correctly totaled and written in figures and words. 
 
16. The Board permits candidates to obtain photocopy of the Answer Book on request in an RTI 
application and also separately as a part of the re-evaluation process on payment of the 
processing charges.  
 
 
56/1/1 – Set  
MARKING SCHEME 
Sr. SECONDARY SCHOOL EXAMINATION, 2020 
Subject: CHEMISTRY 
Q.No. Expected Answer / Value Points 
Distribut
ion of 
Marks 
SECTION - A 
1. Racemic Mixture 1 
2. Polarimeter  1 
3. Pent-2-ene / CH
3
CH=CHCH
2
CH
3
 1 
4. Antiseptic 1 
5. CH
3
I + C
6
H
5
OH 1 
6. A 1 
7. Zn 1 
8. No 1 
9. CH
2
=CH-Cl 1 
10. Branched hydrocarbon part 1 
11. B 1 
12. D 1 
13. C 1 
14. C 1 
15. A 1 
16. iii 1 
17. ii 1 
18. i 1 
19. ii 1 
20. i 1 
  
SECTION – B 
21. 
 
 
 
 
21 
(a) The drugs which are used to control stress / anxiety / tension / mild or severe 
mental diseases 
(b) The drugs which are used to kill or to prevent the growth of micro-organism, 
 applied externally on living tissues. 
OR 
Soap molecules form micelle around the oil droplet or dirt in such a way that 
hydrophobic part interacts with the oil droplet and hydrophilic part projects out. 
Micelles can be washed away on rinsing with water. Thus soap helps in 
emulsification and washing away of oil and fats.   
1 
 
1 
 
 
2 
22. ? = CRT (Volume of solution = 100 mL) 
? = 
 
 
 RT 
? = 
 
  
 
          
   
 
? = 20.5 atm.                          (½ mark may be deducted for no or incorrect unit) 
 
                                                          OR 
½  
 
 
½ 
 
1 
 
22. ?T
f 
(urea) = ?T
f 
(Z) 
   
      
     
 
    
         
    
  
  
 
    
        
 
   
  
 
    
   
 
     
  
 
    
   
 
   
        
    
                            (or by any other correct method) 
                                                (½ mark may be deducted for no or incorrect unit) 
½ 
 
½ 
 
 
 
 
1 
23. (a) 1
st
 order  
(b) No, due to exponential relation / the curve never touches the x-axis. 
1 
 
½ + ½ 
24. a)  
  
b) 
  
 
1 
 
 
 
 
 
 
 
1 
25. (a) K
2
[Zn(OH)
4
] 
(b) [Pt(NH
3
)
6
]Cl
4
 
1 
1 
26. a) (CH
3
)
3
C-OH / tertiary butyl alcohol is formed. 1 
Page 4


General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. To 
avoid mistakes, it is requested that before starting evaluation, you must read and understand 
the spot evaluation guidelines carefully. Evaluation is a 10-12 days mission for all of us. 
Hence, it is necessary that you put in your best efforts in this process. 
2. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be 
done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, answers 
which are based on latest information or knowledge and/or are innovative, they may 
be assessed for their correctness otherwise and marks be awarded to them.  
3. The Head-Examiner must go through the first five answer books evaluated by each evaluator 
on the first day, to ensure that evaluation has been carried out as per the instructions given 
in the Marking Scheme. The remaining answer books meant for evaluation shall be given 
only after ensuring that there is no significant variation in the marking of individual evaluators. 
4. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X”be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
5. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totaled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
6. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
7. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
8. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
10. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours 
every day and evaluate 20 answer books per day in main subjects and 25 answer books per 
day in other subjects (Details are given in Spot Guidelines). 
11. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past:- 
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior School Certificate Examination-2020 
Marking Scheme – CHEMISTRY 
(SUBJECT CODE -043) (PAPER CODE – 56/1/1) 
9. A full scale of marks 0-70 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
12. While evaluating the answer books if the answer is found to be totally incorrect, it should be 
marked as cross (X) and awarded zero (0)Marks. 
  
13. Any unassessed portion, non-carrying over of marks to the title page, or totaling error 
detected by the candidate shall damage the prestige of all the personnel engaged in the 
evaluation work as also of the Board. Hence, in order to uphold the prestige of all concerned, 
it is again reiterated that the instructions be followed meticulously and judiciously. 
 
14. The Examiners should acquaint themselves with the guidelines given in the Guidelines for 
spot Evaluation before starting the actual evaluation. 
 
15. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to 
the title page, correctly totaled and written in figures and words. 
 
16. The Board permits candidates to obtain photocopy of the Answer Book on request in an RTI 
application and also separately as a part of the re-evaluation process on payment of the 
processing charges.  
 
 
56/1/1 – Set  
MARKING SCHEME 
Sr. SECONDARY SCHOOL EXAMINATION, 2020 
Subject: CHEMISTRY 
Q.No. Expected Answer / Value Points 
Distribut
ion of 
Marks 
SECTION - A 
1. Racemic Mixture 1 
2. Polarimeter  1 
3. Pent-2-ene / CH
3
CH=CHCH
2
CH
3
 1 
4. Antiseptic 1 
5. CH
3
I + C
6
H
5
OH 1 
6. A 1 
7. Zn 1 
8. No 1 
9. CH
2
=CH-Cl 1 
10. Branched hydrocarbon part 1 
11. B 1 
12. D 1 
13. C 1 
14. C 1 
15. A 1 
16. iii 1 
17. ii 1 
18. i 1 
19. ii 1 
20. i 1 
  
SECTION – B 
21. 
 
 
 
 
21 
(a) The drugs which are used to control stress / anxiety / tension / mild or severe 
mental diseases 
(b) The drugs which are used to kill or to prevent the growth of micro-organism, 
 applied externally on living tissues. 
OR 
Soap molecules form micelle around the oil droplet or dirt in such a way that 
hydrophobic part interacts with the oil droplet and hydrophilic part projects out. 
Micelles can be washed away on rinsing with water. Thus soap helps in 
emulsification and washing away of oil and fats.   
1 
 
1 
 
 
2 
22. ? = CRT (Volume of solution = 100 mL) 
? = 
 
 
 RT 
? = 
 
  
 
          
   
 
? = 20.5 atm.                          (½ mark may be deducted for no or incorrect unit) 
 
                                                          OR 
½  
 
 
½ 
 
1 
 
22. ?T
f 
(urea) = ?T
f 
(Z) 
   
      
     
 
    
         
    
  
  
 
    
        
 
   
  
 
    
   
 
     
  
 
    
   
 
   
        
    
                            (or by any other correct method) 
                                                (½ mark may be deducted for no or incorrect unit) 
½ 
 
½ 
 
 
 
 
1 
23. (a) 1
st
 order  
(b) No, due to exponential relation / the curve never touches the x-axis. 
1 
 
½ + ½ 
24. a)  
  
b) 
  
 
1 
 
 
 
 
 
 
 
1 
25. (a) K
2
[Zn(OH)
4
] 
(b) [Pt(NH
3
)
6
]Cl
4
 
1 
1 
26. a) (CH
3
)
3
C-OH / tertiary butyl alcohol is formed. 1 
b) C
6
H
5
COCH
3
 / acetophenone is formed 
(or correct chemical equation) 
1 
27. a) C
6
H
5
OH + HCHO , Phenol + formaldehyde 
b) CH
2
= C(Cl) – CH=CH
2
, Chloroprene 
½ + ½ 
½ + ½ 
SECTION - C 
28. 
 
 
 
 
 
28 
(a) (A) ? CH
3
CONH
2
 (B) ? CH
3
NH
2 
(b) (A) ? C
6
H
5
NH
2
  (B) ? C
6
H
5
N
2
Cl 
(c) (A) ? C
6
H
5
CN  (B) ? C
6
H
5
COOH 
 
                                                                  OR 
a) (i) Add Ice cold (NaNO
2
 + HCl) followed by phenol or ß-Naphthol to both the 
   compounds.  
  Aniline forms orange red dye while ethylamine doesn’t.  
ii) Add CHCl
3
 and KOH (alc.) to both the compounds.  
  Aniline gives foul smelling isocyanide while N-Methylaniline doesn’t. 
                                                                  (or any other suitable chemical test) 
b) Butanol > Butanmine > Butane 
½ + ½ 
 
½ + ½ 
½ + ½ 
 
 
1 
 
 
1 
 
 
1 
 
29. (a) Because the – CHO group in glucose is involved in hemiacetal formation 
 and thus is not free / due to cyclic structure of glucose -CHO group is not 
free.  
(b) Because the hydrogen bonds are formed between specific pairs of bases. 
(c) Starch is a polymer of ? - glucose while cellulose is a polymer of ? - 
glucose. 
  
1 
 
 
1 
 
1 
30. 
 
 
 
 
 
 
30 
(a) Because sulphur readily gets oxidized itself to more stable +6 state. 
(b) Because of absence of d-orbital in Fluorine. 
(c) Because size increases from Helium to Radon. / dispersion or van der Waal 
forces increase from Helium to Radon.   
OR 
(a)  MnO
2
+ 4HCl   ?  MnCl
2
 + Cl
2
 + 2H
2
O 
(b) XeF
6
 + KF  ? K
+
[XeF
7
]
-
 
(c) 4I
-
(aq.)
 + 4H
+
(aq.)
 
 + O
2(g)
 ? 2I
2(s)
 + 2H
2
O
(l)
 
 
1 
 
1 
 
1 
 
 
1 
 
1 
 
1 
31. (a) NaCN act as a depressant.  
(b) SiO
2
 act as a flux. / used to remove FeO as slag 
(c) I
2
 is used to convert Ti into volatile compound (TiI
4
). 
1 
1 
1 
32. 
 
 
(or any other correct differences) 
 
1 x 3  
Page 5


General Instructions: - 
 
1. You are aware that evaluation is the most important process in the actual and correct 
assessment of the candidates. A small mistake in evaluation may lead to serious problems 
which may affect the future of the candidates, education system and teaching profession. To 
avoid mistakes, it is requested that before starting evaluation, you must read and understand 
the spot evaluation guidelines carefully. Evaluation is a 10-12 days mission for all of us. 
Hence, it is necessary that you put in your best efforts in this process. 
2. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be 
done according to one’s own interpretation or any other consideration. Marking Scheme 
should be strictly adhered to and religiously followed. However, while evaluating, answers 
which are based on latest information or knowledge and/or are innovative, they may 
be assessed for their correctness otherwise and marks be awarded to them.  
3. The Head-Examiner must go through the first five answer books evaluated by each evaluator 
on the first day, to ensure that evaluation has been carried out as per the instructions given 
in the Marking Scheme. The remaining answer books meant for evaluation shall be given 
only after ensuring that there is no significant variation in the marking of individual evaluators. 
4. Evaluators will mark( v ) wherever answer is correct.  For wrong answer ‘X”be marked.  
Evaluators will not put right kind of mark while evaluating which gives an impression that 
answer is correct and no marks are awarded.  This is most common mistake which 
evaluators are committing. 
5. If a question has parts, please award marks on the right-hand side for each part. Marks 
awarded for different parts of the question should then be totaled up and written in the left-
hand margin and encircled.  This may be followed strictly. 
6. If a question does not have any parts, marks must be awarded in the left-hand margin and 
encircled. This may also be followed strictly. 
7. If a student has attempted an extra question, answer of the question deserving more marks 
should be retained and the other answer scored out. 
8. No marks to be deducted for the cumulative effect of an error. It should be penalized only 
once. 
10. Every examiner has to necessarily do evaluation work for full working hours i.e. 8 hours 
every day and evaluate 20 answer books per day in main subjects and 25 answer books per 
day in other subjects (Details are given in Spot Guidelines). 
11. Ensure that you do not make the following common types of errors committed by the 
Examiner in the past:- 
? Leaving answer or part thereof unassessed in an answer book. 
? Giving more marks for an answer than assigned to it. 
? Wrong totaling of marks awarded on a reply. 
? Wrong transfer of marks from the inside pages of the answer book to the title page. 
? Wrong question wise totaling on the title page. 
? Wrong totaling of marks of the two columns on the title page. 
? Wrong grand total. 
? Marks in words and figures not tallying. 
? Wrong transfer of marks from the answer book to online award list. 
? Answers marked as correct, but marks not awarded. (Ensure that the right tick mark is 
correctly and clearly indicated. It should merely be a line. Same is with the X for incorrect 
answer.) 
? Half or a part of answer marked correct and the rest as wrong, but no marks awarded.  
 
Strictly Confidential: (For Internal and Restricted use only) 
Senior School Certificate Examination-2020 
Marking Scheme – CHEMISTRY 
(SUBJECT CODE -043) (PAPER CODE – 56/1/1) 
9. A full scale of marks 0-70 has to be used. Please do not hesitate to award full marks if the 
answer deserves it. 
12. While evaluating the answer books if the answer is found to be totally incorrect, it should be 
marked as cross (X) and awarded zero (0)Marks. 
  
13. Any unassessed portion, non-carrying over of marks to the title page, or totaling error 
detected by the candidate shall damage the prestige of all the personnel engaged in the 
evaluation work as also of the Board. Hence, in order to uphold the prestige of all concerned, 
it is again reiterated that the instructions be followed meticulously and judiciously. 
 
14. The Examiners should acquaint themselves with the guidelines given in the Guidelines for 
spot Evaluation before starting the actual evaluation. 
 
15. Every Examiner shall also ensure that all the answers are evaluated, marks carried over to 
the title page, correctly totaled and written in figures and words. 
 
16. The Board permits candidates to obtain photocopy of the Answer Book on request in an RTI 
application and also separately as a part of the re-evaluation process on payment of the 
processing charges.  
 
 
56/1/1 – Set  
MARKING SCHEME 
Sr. SECONDARY SCHOOL EXAMINATION, 2020 
Subject: CHEMISTRY 
Q.No. Expected Answer / Value Points 
Distribut
ion of 
Marks 
SECTION - A 
1. Racemic Mixture 1 
2. Polarimeter  1 
3. Pent-2-ene / CH
3
CH=CHCH
2
CH
3
 1 
4. Antiseptic 1 
5. CH
3
I + C
6
H
5
OH 1 
6. A 1 
7. Zn 1 
8. No 1 
9. CH
2
=CH-Cl 1 
10. Branched hydrocarbon part 1 
11. B 1 
12. D 1 
13. C 1 
14. C 1 
15. A 1 
16. iii 1 
17. ii 1 
18. i 1 
19. ii 1 
20. i 1 
  
SECTION – B 
21. 
 
 
 
 
21 
(a) The drugs which are used to control stress / anxiety / tension / mild or severe 
mental diseases 
(b) The drugs which are used to kill or to prevent the growth of micro-organism, 
 applied externally on living tissues. 
OR 
Soap molecules form micelle around the oil droplet or dirt in such a way that 
hydrophobic part interacts with the oil droplet and hydrophilic part projects out. 
Micelles can be washed away on rinsing with water. Thus soap helps in 
emulsification and washing away of oil and fats.   
1 
 
1 
 
 
2 
22. ? = CRT (Volume of solution = 100 mL) 
? = 
 
 
 RT 
? = 
 
  
 
          
   
 
? = 20.5 atm.                          (½ mark may be deducted for no or incorrect unit) 
 
                                                          OR 
½  
 
 
½ 
 
1 
 
22. ?T
f 
(urea) = ?T
f 
(Z) 
   
      
     
 
    
         
    
  
  
 
    
        
 
   
  
 
    
   
 
     
  
 
    
   
 
   
        
    
                            (or by any other correct method) 
                                                (½ mark may be deducted for no or incorrect unit) 
½ 
 
½ 
 
 
 
 
1 
23. (a) 1
st
 order  
(b) No, due to exponential relation / the curve never touches the x-axis. 
1 
 
½ + ½ 
24. a)  
  
b) 
  
 
1 
 
 
 
 
 
 
 
1 
25. (a) K
2
[Zn(OH)
4
] 
(b) [Pt(NH
3
)
6
]Cl
4
 
1 
1 
26. a) (CH
3
)
3
C-OH / tertiary butyl alcohol is formed. 1 
b) C
6
H
5
COCH
3
 / acetophenone is formed 
(or correct chemical equation) 
1 
27. a) C
6
H
5
OH + HCHO , Phenol + formaldehyde 
b) CH
2
= C(Cl) – CH=CH
2
, Chloroprene 
½ + ½ 
½ + ½ 
SECTION - C 
28. 
 
 
 
 
 
28 
(a) (A) ? CH
3
CONH
2
 (B) ? CH
3
NH
2 
(b) (A) ? C
6
H
5
NH
2
  (B) ? C
6
H
5
N
2
Cl 
(c) (A) ? C
6
H
5
CN  (B) ? C
6
H
5
COOH 
 
                                                                  OR 
a) (i) Add Ice cold (NaNO
2
 + HCl) followed by phenol or ß-Naphthol to both the 
   compounds.  
  Aniline forms orange red dye while ethylamine doesn’t.  
ii) Add CHCl
3
 and KOH (alc.) to both the compounds.  
  Aniline gives foul smelling isocyanide while N-Methylaniline doesn’t. 
                                                                  (or any other suitable chemical test) 
b) Butanol > Butanmine > Butane 
½ + ½ 
 
½ + ½ 
½ + ½ 
 
 
1 
 
 
1 
 
 
1 
 
29. (a) Because the – CHO group in glucose is involved in hemiacetal formation 
 and thus is not free / due to cyclic structure of glucose -CHO group is not 
free.  
(b) Because the hydrogen bonds are formed between specific pairs of bases. 
(c) Starch is a polymer of ? - glucose while cellulose is a polymer of ? - 
glucose. 
  
1 
 
 
1 
 
1 
30. 
 
 
 
 
 
 
30 
(a) Because sulphur readily gets oxidized itself to more stable +6 state. 
(b) Because of absence of d-orbital in Fluorine. 
(c) Because size increases from Helium to Radon. / dispersion or van der Waal 
forces increase from Helium to Radon.   
OR 
(a)  MnO
2
+ 4HCl   ?  MnCl
2
 + Cl
2
 + 2H
2
O 
(b) XeF
6
 + KF  ? K
+
[XeF
7
]
-
 
(c) 4I
-
(aq.)
 + 4H
+
(aq.)
 
 + O
2(g)
 ? 2I
2(s)
 + 2H
2
O
(l)
 
 
1 
 
1 
 
1 
 
 
1 
 
1 
 
1 
31. (a) NaCN act as a depressant.  
(b) SiO
2
 act as a flux. / used to remove FeO as slag 
(c) I
2
 is used to convert Ti into volatile compound (TiI
4
). 
1 
1 
1 
32. 
 
 
(or any other correct differences) 
 
1 x 3  
33. (a) Decreases. 
(b) Increases  
(c) Increases 
 
1 
 
1 
1 
 
34. ?T
f
 = K
f
  m 
1.5 = 
     
 
   
 
    
  
 
Mass of ascorbic acid = 5.08 g. 
1 
 
1 
1 
 SECTION – D  
35 (a) E
0
cell = E
o
C
 – E
o
A
 
          = 0.34 – (-0.76) 
         = 1.10V 
?G
o
 = -nFE
o
 
    = -2 ? 1.10 ? 96500 
    = -212300 J/mol or -212.3 kJ/mol 
(b) (i) Pollution free 
 (ii) High efficiency. 
½  
 
½  
 
½  
½  
1 
1 
1 
 
35. 
 
 
 
 
 
 
 
 
 
 
 
 
OR 
(a) (i) Silver wire at 30
o
C because as temperature decreases, resistance  
  decreases so conduction increases. 
 (ii) 0.1 M CH
3
COOH, because on dilution degree of ionization increases 
   hence conduction increases. 
 (iii) KCl solution at 50
o
C, because at high temperature mobility of ions 
increases and hence conductance increases 
(b) 
Electrochemical Electrolytic 
(1) Anode -ve 
 Cathode +ve 
(2) Convert chemical 
 Energy to electrical energy 
Anode +ve  
Cathode -ve 
Convert electrical 
Energy to chemical energy 
(or any other correct differences) 
 
 
1 
 
1 
 
1 
 
 
 
 
1 
 
1