#### 12th Standard Chemistry English Medium Reduced Syllabus Model Question paper - 2021 Part - 2

12th Standard

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Chemistry

Time : 02:45:00 Hrs
Total Marks : 70

Part I

Answer all the questions.

Choose the most suitable answer from the given four alternatives and write the option code with the corresponding answer.

15 x 1 = 15
1. Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true?

(a)

$\Delta { G }_{ f }^{ 0 }$ of sulphide is greater than those for CS2 and H2S

(b)

$\Delta { G }_{ r }^{ 0 }$ is negative for roasting of sulphide ore to oxide

(c)

Roasting of the sulphide to its oxide is thermodynamically feasible

(d)

Carbon and hydrogen are suitable reducing agents for metal sulphides

2. Extraction of gold and silver involves leaching with cyanide ion. silver is later recovered by (NEET-2017)

(a)

Distillation

(b)

Zone refining

(c)

Displacement with zinc

(d)

liquation

3. Which of the following plot gives Ellingham diagram

(a)

$\Delta SVsT$

(b)

$\Delta { G }^{ 0 }VsT$

(c)

$\Delta { G }^{ 0 }Vs\cfrac { 1 }{ T }$

(d)

$\Delta { G }^{ 0 }Vs{ T }^{ 2 }$

4. The basic structural unit of silicates is (NEET)

(a)

$\left( SiO_{ 3 } \right) ^{ 2- }$

(b)

$\left( SiO_{ 4 } \right) ^{ 2- }$

(c)

$\left( Sio \right) ^{ - }$

(d)

$\left( SiO_{ 4 } \right) ^{ 4- }$

5. XeF6 on complete hydrolysis produces

(a)

XeOF4

(b)

XeO2F2

(c)

XeO3

(d)

XeO2

6. Which is the group that decreases the acid strength of phenol?

(a)

-NO2

(b)

-CN-

(c)

-NH2

(d)

Both (a) and (b)

7. The compound that acts as a solvent for Grignard reagent is :

(a)

Ethyl alcohol

(b)

Diethyl ether

(c)

Acetone

(d)

Benzene

8. $\overset { { CH }_{ 2 }-OH }{ \underset { { CH }_{ 2 }-OH }{ | } } \overset { { PI }_{ 3 } }{ \longrightarrow }$ __________ethan-1,2-diol

(a)

ethane

(b)

ethene

(c)

ethyl iodide

(d)

ethyne

9. The ether used in perfumery is ________

(a)

diethyl ether

(b)

dimethyl ether

(c)

methyl phenyl ether

(d)

diphenyl ether

10. The active component of dynamite is _______

(a)

keiselghur

(b)

nitro glycerine

(c)

nitro benzene

(d)

trinitro toluene

11. Nylon -66 is an example of ______ polymer.

(a)

addition

(b)

condensation

(c)

both (a) and (b)

(d)

natural

12. Teflon is an _______ polymer.

(a)

LDPE

(b)

HDPE

(c)

Condensation

(d)

All the above

13. The quality of a soap is described in term of _______

(a)

LDPE

(b)

HDPE

(c)

TFM (Total fatty matter)

(d)

LFM (Lowfatty matter)

14. Pain killers are known a _______

(a)

antipyretics

(b)

analgesics

(c)

antibiotics

(d)

antiseptics

15. Iodoform is ________

(a)

antibiotic

(b)

antiseptic

(c)

disinfectant

(d)

both (a) and (c)

1. Part II

Answer any 6 questions. Question no. 24 is compulsory.

9 x 2 = 18
16. Write a short note on anamolous properties of the first element of p-block

17. Why fluorine is more reactive than other halogens?

18. Define average rate and instantaneous rate

19. Give the IUPAC names of
(i) CH3CH(OH)CH2OH
(ii) HO-CH2-CH2-OH
(iii) ${ { CH } }_{ 3 }-\underset { \overset { | }{ OH } }{ CH } -COOH$

20. Write the IUPAC names of
(a) C2H5OCH3
(b) C6H5OC2H5

21. Which of the following does not give iodoform reaction?

22. Write any three uses of formic acid.

23. Write a note on Claisen Condensation.

24. Identify A and B in the following sequence of reactions.${ CH }_{ 3 }-Br\xrightarrow [ 675k\\ Red\quad hot\quad si\quad tube ]{ { HNO }_{ 3 } } A\xrightarrow [ NaOH ]{ { Cl }_{ 2 } } B$

1. Part III

Answer any 6 questions. Question no. 33 is compulsory.

9 x 3 = 27
25. Copper and silver lie low in the electrochemical series and yet they are found in the combined state as sulphides in nature. Comment.

26. Write the molecular formula and structural formula for the following molecules.
a) Nitric acid
b) dinitrogen pentoxide
c) phosphoric acid
d) phosphine

27. Define ionic product of water. Give its value at room temperature.

28. The conductivity of a 0.01M solution of a 1 :1 weak electrolyte at 298K is 1.5$\times$10-4 S cm−1.
i) molar conductivity of the solution
ii) degree of dissociation and the dissociation constant of the weak electrolyte
Given that
$\lambda^{0}_{catlon}=248.2\quad S$ cm2 mol-1
$\lambda^{0}_{anlon}=51.8\quad S$ cm2 mol-1

29. Arrange the following solutions in the decreasing order of specific conductance.
i) 0.01M KCl
ii) 0.005M KCl
iii) 0.1M KCl
iv) 0.25 M KCl
v) 0.5 M KCl

30. What are enzymes? Write a brief note on the mechanism of enzyme catalysis.

31. Arrange the following
i. In increasing order of solubility in water, C6H5 NH2,(C2H5)2 NH,C2H5NH2
ii. In increasing order of basic strength
a) aniline, p- toludine and p – nitroaniline
b) C6H5 NH2,C6H5 NHCH3,C6H5NH2 ,p-Cl-C6- H4-NH2
iii. In decreasing order of basic strength in gas phase
(C2H5)NH2 ,(C2H5)NH, (C2H5)5N and NH3
iv. In increasing order of boiling point
C6H5OH, (CH3)2NH, C2H5NH2
v. In decreasing order of the pKb values
C2H5NH2, C6H5NHCH3.(C2H5) NH and CH3NH2
vi. Increasing order of basic strength
C2H5NH2,C6H5NH(CH3)2 ,(C2H5)2 NH and CH3NH2
vii. In decreasing order of basic strength

32. How will you prepare propan – 1- amine from
i) butane nitrile
ii) propanamide
ii) 1- nitropropane

33. Explain the mechanism of cleansing action of soaps and detergents

1. Part IV

Answer all the questions.

10 x 5 = 50
34. Why do zirconium and Hafnium exhibit similar properties?

35. Which metal in the 3d series exhibits +1 oxidation state most frequently and why

36. Atoms X and Y form bcc crystalline structure. Atom X is present at the corners of the cube and Y is at the centre of the cube. What is the formula of the compound?

37. Predict the product A,B,X and Y in the following sequence of reaction

38. Ail organic compound. (A) C7H6O reduces Tollens reagent.. Compound (A) reacts with acetic anhydride in the presence of anhydrous sodium acetate and gives an unsaturated acid (B). Compound (A) reacts with acetone in the presence of alkali and gives (C). What are (A)(B) and (C) Explain the reactions.

39. What happens when ethylamine is treated with
(i) CHCl3/NaOH
(ii) CS2
(iii) C6H5CHO.

40. Write the differences between nitro methane and nitro benzene

41. List the importance of proteins in biological processes.

42. What are narcotic and non – narcotic drugs. Give examples

43. Write a note on drug target interaction.