CBSE Marking Scheme - Class XII Chemistry - CBSE 2012

Hi readers,  

CBSE Question Paper for Chemistry will be of 70 marks and students will have 3 hours to complete the paper. CBSE Board has prescribed certain guidelines according to CBSE marking scheme. The question paper will have no overall choice. However, there will be internal choices in the question paper. The students shall get due credit for precise answers as per CBSE Marking Scheme. The table below gives weightage of topics in CBSE Chemistry Question paper.

CBSE Marking Scheme in Detail for Chemistry

Unit	Marks (No. of questions)
Solid State	4 (2)
Solutions	5 (1)
Electrochemistry	5 (2)
Chemical Kinetics	5 (3)
Surface Chemistry	4 (2)
General Principles and processes of isolation of elements	3 (1)
p-block elements	8 (4)
d& f block elements	5 (1)
Coordination Compounds	3 (2)
Haloalkanes and Haloarenes	4 (2)
Alcohols, Phenols and Ethers	4 (2)
Aldehydes,Ketones & Carboxylic acids	6 (2)
Organic Compounds containing Nitrogen	4 (2)
Biomolecules	4 (2)
Polymers	3 (1)
Chemistry in Everyday Life	3 (1)

Weightage to Questions

CBSE question paper for Chemistry shall consist of 8 very short answer questions. The very short answer questions will carry 1 mark each. The paper will have two types of short answer questions with 2 and 3 marks respectively. There will also be 3 long answer questions which will require students to write answers in detail. The 5 long answer questions will carry 5 marks each. CBSE Chemistry question paper will be of 70 marks in total. The students will be given internal choice on any one question of 3 marks, any one question of 2 marks and all three long answer questions. In all, there will be internal choices on five questions.

Sample Question with CBSE marking scheme for Chemistry

The marking scheme for answer to sample question in Chemistry paper is given below:
Question (3 marks)

1. Give Chemical Tests to distinguish between:
i) Isopropyl alcohol and n-propylalcohol
ii) Phenol and alcohol
iii) Methyl ethanoate and Ethyl ethanoate

Answer 1 :

i) On adding NaOH/I2 or NaOI and heating, Isopropyl alcohol forms yellow ppt of iodoform(CHI3) whereas n-propyl alcohol does not. (or any other suitable test)
ii) Phenol and alcohol On adding neutral FeCl3 solution, Phenol forms red-violet complex whereas alcohol does not. (or any other suitable test)
iii) methyl ethanoate and ethyl ethanoatelodoform test – On hydrolysis, ethylethanoate gives ethanol which on heating with NaOI gives yellow ppt of CHI3 whereas Methyl Ethanoate on hydrolysis gives Methanol which does not form Iodoform with NaOI 1*3=3

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