CBSE Class 12 Chemistry Revision (2). 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. Name the non-stoichiometric point defect responsible for colour in alkali halides?
2. What type of alignment in crystals makes them ferrimagnetic?
3. Write equation for the following reactions;
a) Wurtz – Fittig reaction
b) Friedel – Crafts acylation of Chlorobenzene
4. Explain the following terms:
b) Tetrahedral void
5. A metallic oxide crystallizes in a hexagonal closed packed array of oxide ions with two out of every three octahedral voids occupied by the metal ions. Derive the formula of the metallic oxide.
6. An optically active compound having molecular formula C6H13Br reacts with aq.KOH to give a racemic mixture of products. Write the mechanism involved in the reaction.
7. a) Give a chemical test to distinguish between the following pairs of compounds:
Phenyl chloride and Benzyl chloride
b) Arrange the following compounds in the increasing order of the reactivity towards the reaction with caustic alkali:
Chlorobenzene, 4-chloro-1-methyl-benzene, 4- nitrochlorobenzene and 2,4,6-trinitrochlorobenzene
c) Write the IUPAC name of the following compound:
8. Copper crystallizes into an fcc lattice with edge length 3.61 x 10-8cm. Calculate the density of copper. [Given Cu = 63.5g mol-1]
9. a) Identify the chiral molecule in the following:
Pentan -2-ol or Pentan-3-ol
b) Give reason:
i) Haloalkanes react with KCN to form alkyl cyanides as main product while AgCN forms isocyanides as the chief product.
ii) Why is sulphuric acid not used during the reaction of alcohols with KI?
10. How will you bring about the following conversions:
a) 1- Bromopropane to 2,3- dimethylbutane
b) Ethanol to propanenitrile
c) tert-Butyl bromide to isobutylbromide
11. A sample of ferrous oxide has actual formula Fe0.93O1.00. In this sample what fraction of metal ions are Fe2+ ions? What type of non-stoichiometric defect is present in this sample?
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