Tamil Nadu State Board Class 12 Marking Scheme – Chemistry

Tamil Nadu State Board Chemistry Blueprint for Class 12

Tamil Nadu Board of Higher Secondary Education Marking Scheme / Blueprint for Class 12 Chemistry is given below.

BLUE PRINT – CHEMISTRY – Higher Secondary – Second Year

Instructions to the Question Paper Setters

Blue Print for XII Chemistry
Time : 3 hours
Max. Marks : 150

Part- I

30×1=30 marks

Choose the Correct answer : answer all questions.
Question numbers : from 1 to 30.
Distribution of questions : 10-Inorganic, 10-Physical and 10- Organic Portions.

Part – II

15 x 3 = 45 marks

Answer in one or two sentences : Question number from 31-51.
Answer 15 questions out of 21 questions.
Question number 31 -37 (7) from Inorganic
Question number 38 – 44 (7) from Physical
Question number 45 – 51 (7) from Organic

Part – III

7 x 5 = 35 marks

Answer any Seven questions choosing atleast two from each section A, B and C

Section – A – Inorganic 4 questions 52-55 (one problem)
Section – B – Physical 4 questions 56-59 (one problem)
Section – C – Organic 4 questions 60-63 (one mechanism)

Part – IV

4 x 10 = 40 marks

Question number 70 is compulsory consisting of problems carrying 10 marks (either or type)

70 (a) Organic Problem – 5 marks
(b) Inorganic Problem – 5 marks
OR
(c) Organic Problem – 5 marks
(d) Physical Problem – 5 marks

Question number 64 and 65 – Inorganic
Question number 66 and 67 – Physical
Question number 68 and 69 – Organic
answer any three from question number 64-69

Note : 1. In Part-III five mark questions no subdivisions are allowed.

2. In Part-IV ten mark questions there should be two sub divisions each with 5 marks.

3. 60% of the total layout of questions (for 233 marks) must be asked from self evaluation questions of all branches of chemistry
(Inorganic, Physical and Organic) in equal propotions.

4. Problems can be asked from any lesson or chapter instead of descriptive questions and vice versa.

5. Problems

Part – I MCQ 4 questions 4 x 1 = 4 (1+2+1)

Part – II 3 questions 3 x 3 = 9 (1+1+1)

Part – III Inorganic – 1 question 2 x 5 = 10
Physical – 1 question

Part – IV question no 70 is compulsory,
either or choice 2 x 10 = 20 marks
maximum marks 4 + 9 +10 + 20 = 43 marks.

6. A question paper should not contain problems for more than 43 marks out of 233 marks.

7. Organic reaction mechanicsm may be asked one in Part-III Section-C (organic) and another in Part-IV question number 68 or
69 subdivision for 5 marks.

8. List of Mechanisms

(i) Aldol condensation of acetaldehyde …………………281-282
(ii) Aldol condensation of acetone ………………………..282-283
(iii) Crossed aldol condensation …………………………….. 283
(iv) Cannizaro reaction …………………………………………. 300
(v) Claisen or Claisen schmidt reaction …………………… 301
(vi) Mechanism of esterification ……………………………… 336
(vii) Kolbe’s reaction …………………………………………….. 355
(viii)Bromination of salicylic acid ……………………………… 356
(ix) Nitration of benzene …………………………………….. 387-388
(x) Hoffmann’s bromamide reaction ……………………..398-399
(xi) Reaction of aniline with carbondisulphide………..411 – 412

For other organic reactions mechanisms need not be expected.

9. One mark question from numbered tables should not be asked.

10. For all questions answers must be available in the prescribed +2 Chemistry text book.

11. Electronic configuration of elements for which extraction is given in the book may be asked for one mark questions.

12. A question paper should not contain more than 2 questions from the mechanism.

13. Numerical data given in the form of numbered tables in all branches should not be asked in the form of questions.

14. No questions should be asked from the boxed (including deleted portion and chronology) portions of lessons.

15. For theory examination logarithmic tables are allowed.

16. One mark, three marks and five marks problems (in both Part-III & Part-IV) may be given in lessons 1, 3, 4, 6 and 7 for inorganic
chemistry, lessons 8, 9, 10, 11, 13 and 14 for physical chemistry and lessons 16, 17, 18, 19 and 20 for organic chemistry.

17. Inorganic and Organic problem
a) For one mark – Identification of – A.
b) For three marks – Identification ‘A’ and ‘B’ with explanation.
c) For five marks – Identification ‘A’, ‘B’ and ‘C’ with explanation.

Modified Instructions Regarding

XII Chemistry Practicals
Max. Marks : 50

Internal Assesment : 20 Marks
1. Record work 10 Marks
2. Project work 10 Marks

Volumetric Analysis : 18 Marks

1. Simple or Short procedure 5 marks
2. Titre value – 1st Titration 5 marks
3. Titre value – 2nd Titration 5 marks
4. Calculations 3 marks

Note :

1. Titre value upto 2% error 5 marks
2% to 3% error 4 marks
3% to 4% error 3 marks
4% to 5% error 2 marks
above 5% error 1 mark

2. Marks for calculations

Normality calculation and 1st Titration caluculation 1 mark
2nd Titration calculation 1 mark
weight calculation 1 mark

3. Usage of calculators is allowed

4. Repetition of Questions in Volumemetric analysis can be permitted if it is required.

Mixture Salt Analysis 12 marks

1. Preliminary Tests

Flame Test, Ash Test, Action of dil HCl, Cu turnings Test and Chromyl Chloride Test 2 marks

2. Sodium Carbonate Extract Preparation and Tests 2 marks

3. Group Separation (Including ammonium ion ) 2 marks

4. Group Analysis (Including ammonium ion ) 2 marks

5. Confirmatory Tests and Results (for all four radicals 4 marks

Note :

1. For each radical one confirmatory Test is enough

2. Any one of the Positive Tests can be written as confirmatory Test for all the four radicals.

3. Just spotting of radicals ½ mark for each radical.

4. Writing Conformatory Test and Result alone 1 mark for each radical.

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