#### 12th Standard Chemistry English Medium Reduced Syllabus Important Questions - 2021 Part - 2

12th Standard

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Chemistry

Time : 02:45:00 Hrs
Total Marks : 165
Multiple Choice Questions
15 x 1 = 15
1. The element that does not show catenation among the following p-block elements is

(a)

Carbon

(b)

silicon

(c)

(d)

germanium

2. Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?

(a)

Br2 > I2 > F2 > Cl2

(b)

F2 > Cl2 > Br2 > l2

(c)

I2 > Br2 > Cl2 > F2

(d)

Cl2 > Br2 > F2 > I2

3. Which of the following d block element has half filled penultimate d sub shell as well as half filled valence sub shell?

(a)

Cr

(b)

Pd

(c)

Pt

(d)

none of these

4. The most common oxidation state of actinoids is

(a)

+2

(b)

+3

(c)

+4

(d)

+6

5. The general electronic configuration of d-block elements can be written as __________

(a)

[Noble gas]n - 1d1-10 ns1-2

(b)

[Noble gas]n - 1d-10 n1-6

(c)

[Noble gas]n - 2 d10 ns1-2

(d)

[Noble gas]n - 2 d10 ns1-6

6. Choose the correct statement

(a)

Square planar complexes are more stable than octahedral complexes

(b)

The spin only magnetic moment of [Cu(Cl)4]2- is BM and it has square planar structure.

(c)

Crystal field splitting energy $\left( { \Delta }_{ 0 } \right)$ [FeF6]4- is higher than the $(\Delta _{ 0 })$ $[Fe(CN)6]{ { 4 }^{ - } }$

(d)

crystal field stabilization energy of [V(H2O)6]2+ is higher than the crystal field stabilization of [Ti(H2O)6]2+

7. Which among the following square planar complexes will exhibet geometrical isomerism?

(a)

[Ma2B2]

(b)

[MA2BC]

(c)

[M(xy)]

(d)

all the above

8. The type of isomerism found in the complexes [Co(NO2)(NH3)5]SO4 and [Co(SO4)(NH3)5] NO2

(a)

Hydrate isomerism

(b)

Coordination isomerism

(c)

(d)

Ionisation

9. Werner's theory was not able to explain______________ of coordination compounds

(a)

colour

(b)

magnetic properties

(c)

both (a) and (b)

(d)

neither (a) nor (b)

10. Schottky defect in a crystal is observed when

(a)

unequal number of anions and anions are missing from the lattice

(b)

equal number of anions and anions are missing from the lattice

(c)

an ion leaves its normal site and occupies an interstitial site

(d)

no ion is missing from its lattice

11. Schottky defects contains

(a)

Cation vacancies only

(b)

Cation vacancies and interstitial cations

(c)

Equal number of cation and anion vacancies

(d)

Anion vacancies and interstitial anions

12. Ostwald's dilution law is applicable in the case of the solution of

(a)

CH3COOH

(b)

NaCI

(c)

NaOH

(d)

H2SO4

13. Henderson equation for a weak acid and its salt is

(a)

pH= pKb+log (Salt) / (Acid)

(b)

pH = pKa + log (Salt) / (Acid)

(c)

pH = pKa +log (Salt) / (Base)

(d)

pH = pKa + log (Acid) / (Salt)

14. The impurity present in the colloidal particle is

(a)

electrolytes

(b)

solute

(c)

both (a) and (b)

(d)

neither (a) or (b)

15. Lower halogenated ethers can be converted into higher ethers by using _______ reagent.

(a)

Grignard

(b)

Tollen's

(c)

Fehling's

(d)

none of the above

16. 2 Marks
15 x 2 = 30
17. Name some elements that occur as native elements.

18. Name the building block of zeolites. Why zeolites have high porosity?

19. Give the oxidation state of halogen in the following.
a) OF2
b) O2F2
c) Cl2O3
d) I2O4

20. (i) Give correct order of boiling point of hydride of group 17.
(ii) Fluorine exhibits only -1 oxidation state whereas other halogens show +1, +3, +5 and +7 oxidation state also Explain.

21. Ni2+ is identified using alcoholic solution of dimethyl glyoxime. Write the structural formula for the rosy red precipitate of a complex formed in the reaction.

22. Give the names of two complexes which are used in medicines.

23. Give an example for the complexes possessing co-ordination number 8 and 7

24. What are the limitations of Ostwald's dilution law?

25. Write the Nernst equation.

26. Can we use nucelophiles such as NH3,CH3- for the Nucleophilic substitution of alcohols

27. Explain why phenol does not undergo substitution of the -OH group like alcohol.

28. Write the tests to differentrate phenol and alcohol.

29. Explain Schotten - Baumann reaction.

30. Write short notes on the following
i. Hofmann’s bromide reaction
ii. Ammonolysis
iii. Gabriel phthalimide synthesis
iv. Schotten – Baumann reaction
v. Carbylamine reaction
vi. Mustard oil reaction
vii. Coupling reaction
viii. Diazotisation
ix. Gomberg reaction

31. ${ CH }_{ 3 }{ NO }_{ 2 }\underrightarrow { { Sn }_{ 2 }/HCl } A\xrightarrow [ CalcoholicKOH ]{ { CH }Cl_{ 3 } } B\underrightarrow { { H }_{ 2 }/P }$ Identify A,B and C.

32. 3 Marks
15 x 3 = 45
33. Write the complete set of reactions occurring in the zone of reduction in the blast furnace in the metallurgy of iron.

34. Write a note on metallic nature of p-block elements

35. Explain the commercial method of preparation of nitric acid. (or) How nitric acid is prepared by Ostwald's process

36. An element A occupies group number 17and period number 2) is the most electronegative element. Element A reacts with another element B) which occupies group number 17 and period number 4) to give a compound Compound C undergoes sp3d2 hybridsation and has octahedral structur. Identify the elements a and B and the compound C.Write the reactions.

37. What are the general properties of f-block elements? (Lanthanides and Actinides)
(i) Electronic configuration
(ii) Oxidation state

38. Do transition elements form complex co-ordinate compounds?

39. Which is the last element in the series of the actinoids? Write the electronic configuration of this element comment on the possible oxidation state of this element.

40. Write the postulates of Werner’s theory

41. Why tetrahedral complexes do not exhibit geometrical isomerism

42. Derive an expression for Ostwald’s dilution law

43. What is Henderson equation?

44. How is phenol prepared form
i) chloro benzene
ii) isoprophy benzene

45. Account for the following:
(a) Lower members of alcohols are soluble in water but higher members are not.
(b) Alcohols cannot be used as solvent for Grignard reagent.

46. How will you prepare phenol (i) From chloro benzene (ii) From benzene sulphonic acid?

47. How are the following compounds obtained from benzene diazonium chloride?
(i) phenol
(ii) ester
(iii) p-hydroxy azo benzene

48. 5 Marks
15 x 5 = 75
49. Suggest a reason why HF is a weak acid, whereas binary acids of the all other halogens are strong acids.

50. What are the properties of inter halogen compounds?

51. Describe the variable oxidation state of 3d series elements.

52. Justify the following statement.
"Elements of the first transition series possess many properties different from those of heavier transition elements".

53. Give the postulates and limitation of Werner's theory of co-ordination compounds.

54. What is meant by stability of a co-ordination compound in solution? State the factors which govern stability of complexes.

55. Write note on impurity defect?

56. Derive Henderson - Hasselbalch equation

57. Derive an expression for Nernst equation

58. Write the Nernst equation for the half cell Zn2+(aq)/ Zn(s)

59. Phenol is distilled with Zn dust followed by friedel – crafts alkylation with prophyl chloride to give a compound B, B on oxidation gives (c) Indentify A,B and C.

60. How would you distinguish between (i) methyl alcohol and ethyl alcohol (ii) benzyl alcohol and phenol, (iii) ethyl alcohol and benzyl alcohol?

61. An organic compound 'A is a sodium salt of phenolic acid with molecular formula C7H5O3Na. 'A on heating with soda lime gives compound 'B' of molecular formula C6H6O. 'B' gives violet colour with neutral ferric chloride. 'B' on treatment with C6H5COCI in the presence of NaOH gives an ester 'C' Identify 'A', 'B' and 'C'. Explain the reactions.

62. An organic compound A (C7H6O) forms a bisulphite. A when treated with alcoholic KCN forms B (C14H12O2) and A on refluxing with sodium acetate and acetic anhydride forms an add C (C9HsO2). Identify A, B and C. Explain the conversion of A to Band C.

63. Draw a flow chart to show classification of nitro compound giving examples for each type.