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JKBOSE || CLASS 12TH MODEL PAPER FOR CHEMISTRY

JKBOSE || CLASS 12TH MODEL PAPER FOR CHEMISTRY

 

guess paper

download here Chemistry paper_

Long Answer Type Questions:

1. What is solubility? Explain the effect of temperature and pressure on the
solubility of gases in liquids.
OR JKBOSE || CLASS 12TH MODEL PAPER FOR BIOLOGY

What is colligative property? How is the molecular mass of a solute calculated from
an elevation in boiling point? 1 gms of a non-electrolyte solute dissolved in 50g of
benzene lowered the freezing point of benzene by 0.40 K. The Kb value of benzene
5.12 KKgmol-1. Find the molar mass of the solute. 5 marks
2. Why molar conductivity of weak electrolytes cannot be calculated from
extrapolation method? Explain how the molar conductivity of weak electrolytes is
calculated from Kohlrauch’s law?
OR
Depict a galvanic cell in which the reaction is
Zn(s) + Cu2+(aq) Zn2+(aq) + Cu(s)
(i) Which of the electrodes is negatively charged?
(ii) What are the carriers of current in the cell?
(iii) What is the individual reaction at each electrode?
(iv) What are the functions of salt bridge? 5 marks
3. Name the oxoacids of Phosphorus. Predict their basicity form their structure.
Which of the two H3PO3 and H3PO4 is stronger?

OR

What are interhalogens? How are they produced? Give the structure of IF7. 5marks

4. How will you distinguish between?
(i) Ethanol and acetone
(ii) acetaldehyde and benzaldehyde
(iii) Tollen’s and Fehling’s test?
OR
Describe the following.
(i) Cannizaro’s reaction
(ii) Aldol condensation
(iii) Cross Aldol condensation 5marks

SECTION B

Short Answer Type Questions:

5. In a solid, there is defect due to missing of equal number of opposite ions from
normal lattice site. 3 marks
(i) Which type of point defect is it?
(ii) What are the effects of this defect on the density and stability of such
solids?
(iii) Name a solid which can have such defect.
6. What is meant by reaction rate? Give symbolic expression and units for the
reaction 3 marks
CO (g) + NO2 (g) CO2 (g) + NO(g)
7. Write the hybridization and also draw the molecular structure of following.
3 marks

XeF2, XeF4, XeF6

8. Briefly describe Freundlich adsorption isotherm. 3 marks
9. How pure alumina is prepared form bauxite in Baeyer’s process? Give the
reaction of each step. 3 marks
10.Atomic radius of Cu is greater than Cr but ionic radius of Cr2+ is greater than
Cu2+. Why? 3 marks
11. How will you distinguish between 10
, 20
and 30
alcohols by Victor Meyer’s
method? 3 marks
12. Amines are basic in nature. Justify. 3 marks

SECTION C

Very Short Answer Type questions:

13. Freons cause destruction of ozone layer. Explain. 2 marks
14. Why CN-

and SCN- are known as Ambidient ligands? What type of isomerism is
caused by such ligands? 2 marks
15. Give cyclisation of Glucose. 2 marks
16. What are fat soluble and water soluble vitamins? 2 marks
17. Explain SN2 mechanism in alkyl halides. 2 marks
18. What happens to natural rubber when it is heated with sulphur? What is the
process known as? 2 marks

19. What are antibiotics and antipyretics? Give Example? 2 marks
20. What is lanthanide contraction? How it is caused? 2 marks

SECTION A

Very Short Answer Type Questions

21. What is the effect of mechanical pressure on a piezoelectric crystal? 1 mark
22. Give the units of zero order reaction. 1 mark
23. What is CMC? 1 mark
24. What is the coordination number of central metal atom in [Fe (C2O4)3]
3- ?

1 mark
25. RX + NaOR _____ + ________ 1 mark
26. Give the reaction for converting acid chlorides to corresponding aldehydes.
Name the reaction. 1 mark
27.Name one biodegradable polymer. 1 mark
28.The correct structure of drug paracetamol is 1 mark
(i)
HO COCH3
(ii)
HO NHCOCH3
(iii)
HO CONH2
(iv)
Cl CONH2

29. A first order reaction is 75% complete after 32 minutes. When 50% of the
reaction was complete? 1 mark
(i) 4 minutes
(ii) 8 minutes
(iii) 16 minutes
(iv) 32 minutes
30. Which of the following is the most basic compound. 1 mark
(i) Benzalamine
(ii) Aniline
(iii) Acidamide
(iv) Para nitro aniline

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