CBSE CLASS XII
Q. 1. Among the isomeric alkanes of molecular formula C5H12, identify the one that on photochemical chlorination yields (i) A single monochloride (ii) Three isomeric monochlorides. (1 mark)
Q. 2. While separating a mixture of ortho and para nitrophenols by steam distillation, name the isomer which will be steam volatile. Give reason. (1 mark)
Q. 3. Write the IUPAC name of the following. (2 mark)
Q. 4. With the help of an example discuss the stereo chemistry involved in SN1 and SN 2 mechanism. (2 marks)
Q. 5. Explain Saytzeff rule by taking suitable examples. (2 marks)
Q. 6. Draw the structures of all isomeric alcohols of molecular formula C5H12O and give their IUPAC names. Classify these isomers of alcohols as primary, secondary and tertiary alcohols. (2 marks)
Q. 7. Nitro group increases the reactivity of chlorobenzene when attched to o and p- position but not at meta position? Explain? Write the mechanism also. (3 marks)
Q. 8. Account for the following. (3 marks)
Q. 9. (a) Explain the fact that in aryl alkyl ethers (i) the alkoxy group activates the benzene ring towards electrophilic substitution and (ii) it directs the incoming substituents to ortho and para positions in benzene ring. (2 mark)
(b) Arrange the following compounds in increasing order of their acid strength: (1 mark)
Propan-1-ol, 2,4,6-trinitrophenol, 3-nitrophenol, 3,5-dinitrophenol, phenol, 4-methylphenol
Q. 10. Give equations of the following reactions: (3 mark)
Q. 11. How will you distinguish between the following: (3 marks)
Q. 12. How will you bring about the following conversions in not more than two steps. (5 marks)
Q. 13. Explain the following with the help of suitable examples: (5 marks)
(a) Limitation of Williamsons synthesis (b) Stephen reaction. (c) Hell-Volhard-Zelinsky reaction (d) Aldol Condensation (e) Wolff-Kishner reduction.
Q. 14. (a) An organic compound (A) (molecular formula C8H16O2) was hydrolysed with dilute sulphuric acid to give a carboxylic acid (B) and an alcohol (C). Oxidation of (C) with chromic acid produced (B). (C) on dehydration gives but-1-ene. Write equations for the reactions involved
(b) Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.
Q. 15. Primary alkyl halide C4H9Br (a) reacted with alcoholic KOH to give compound (b). Compound (b) is reacted with HBr to give (c) which is an isomer of (a). When (a) is reacted with sodium metal it gives compound (d), C8H18 which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of (a) and write the equations for all the reactions.
(ii) Out of C6H5CH2Cl and C6H5CHClC6H5, which is more easily hydrolysed by aqueous KOH.
Q. 16. (a) Write the reactions of glucose with (i) HI (ii)HNO3 (iii)(CH3CO)2O
(b) Discuss the amphoteric nature of amino acid with suitable example.
Q. 17. (a) Discuss the following
(b) What is glycogen? How is it different from starch?
(c) Draw the cyclic structures of anomers of glucose.
Q. 18. (a) Compound A of molecular formula C3H7Br, yields a compound B of molecular formula C3H8O when treated with aq. NaOH. On oxidation the compound B yields a ketone C. Compound C on treating with methyl magnesium bromide and then H2O in acidic medium gives tertiary butyl alcohol. Deduce the structures of A, B and C and write the reactions involved. (3 marks)
(b) Draw the structures of major mono halo products in each of the following reactions. (2 marks)
Q. 19. (a) Discuss the chemistry involved in Brown ring test for nitrate ion. Give equations also. 2 marks
(b) Complete the following equations: 3
(a) Account For the Following: 3
(b) Discuss the quantitative method for estimating O3 gas. (2 marks)
Q. 20. (i) What are interstitial compounds? Why are such compounds well known for transition metals? (1 marks)
(ii) How is the variability in oxidation states of transition metals different from that of the non transition metals? Illustrate with examples. (1 marks)
(iii)Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate? (2 + 1 marks)
(i) Account for the following. (1 x 3 marks)
(ii) How does acidified solution of potassium dichromate react with (a) FeSO4 and (b) H2S?
Paper By Mr. Ankit