CBSE Class 12 Chemistry Revision (3). CBSE issues sample papers every year for students for class 12 board exams. Students should solve the CBSE issued sample papers to understand the pattern of the question paper which will come in class 12 board exams this year. The sample papers have been provided with marking scheme. It’s always recommended to practice as many CBSE sample papers as possible before the board examinations. Sample papers should be always practiced in examination condition at home or school and the student should show the answers to teachers for checking or compare with the answers provided. Students can download the sample papers in pdf format free and score better marks in examinations. Refer to other links too for latest sample papers.
1.What type of semiconductor is obtained when silicon is doped with arsenic?
2.How are cation vacancies created in KCl crystal?
3.Write equation for the following:
a) Swarts reaction
b) Friedel Crafts nitration of Chlorobenzene
4.Explain the following terms:
a) Crystal lattice
5.Distinguish between orthorhombic and triclinic unit cells on the basis of :
a) Crystal parameters
b) Bravais lattices
7.a) Give a chemical test to distinguish between the following pairs:
1- Chloropropene and 3-Chloropropene
b) Which compound of the following pairs will react in SN2 reaction with OH-
(CH3)3CCl or CH3Cl
c) Write the IUPAC name of the following compound:
8.Determine the type of cubic lattice to which a given crystal belongs if it has edge length of 290 pm and density is 7.80g cm-3. (Molecular mass = 56g mol-1 )
9.How will you bring about the following conversions:
a) Benzene to p-nitrochlorobenzene
b) Propene to 1-Propanol
c) 2-Bromopropane to Hexane
10. Analysis shows that nickel oxide has formula Ni0.98O1.00. What fraction of nickel exists as Ni2+ and Ni3+ ions?
11.a) Define racemization.
b) Give reason:
i) Vinyl chloride is unreactive in nucleophilic substitution reactions.
ii) P-Dichlorobenzene has higher melting point than those of o- and m- isomers.
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