#### 12th Standard Chemistry English Medium Transition and inner transition Elements Reduced Syllabus Important Questions 2021

12th Standard

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 100

Multiple Choice Questions

15 x 1 = 15
1. Sc( Z = 21) is a transition element but Zinc (z = 30) is not because

(a)

both Sc3+ and Zn2+ ions are colourless and form white compounds

(b)

in case of Sc, 3d orbital are partially filled but in Zn these are completely filled

(c)

last electron as assumed to be added to 4s level in case of zinc

(d)

both Sc and Zn do not exhibit variable oxidation states

2. 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

3. The catalytic behaviour of transition metals and their compounds is ascribed mainly due to

(a)

their magnetic behaviour

(b)

their unfilled d orbitals

(c)

their ability to adopt variable oxidation states

(d)

their chemical reactivity

4. The correct order of increasing oxidizing power in the series

(a)

VO2+ < Cr2O72- < MnO4-

(b)

Cr2O72- < VO2+ < MnO4-

(c)

Cr2O72- < MnO4- < VO2+

(d)

MnO4- < Cr2O72- < VO2+

5. The alloy of copper that contain Zinc is

(a)

Monel metal

(b)

Bronze

(c)

bell metal

(d)

brass

6. Which of the following does not give oxygen on heating?

(a)

K2Cr2O7

(b)

(NH4)2Cr2O7

(c)

KClO3

(d)

Zn(ClO3)2

7. Which of the following statements is not true?

(a)

on passing H2S, through acidified K2Cr2O7 solution, a milky colour is observed

(b)

Na2Cr2O7 is preferred over K2Cr2O7 in volumetric analysis

(c)

K2Cr2O7 solution in acidic medium is orange in colour

(d)

K2Cr2O7 solution becomes yellow on increasing the PH beyond 7

8. Permanganate ion changes to ________ in acidic medium

(a)

MnO42−

(b)

Mn2+

(c)

Mn3+

(d)

MnO2

9. Which one of the following statements related to lanthanons is incorrect?

(a)

Europium shows +2 oxidation state

(b)

The basicity decreases as the ionic radius decreases from Pr to Lu.

(c)

All the lanthanons are much more reactive than aluminium

(d)

Ce4+ solutions are widely used as oxidising agents in volumetric analysis.

10. Which of the following lanthanoid ions is diamagnetic?

(a)

Eu2+

(b)

Yb2+

(c)

Ce2+

(d)

Sm2+

11. Hybridisation of chromium ions and dichromate ions is

(a)

Sp2

(b)

Sp3d

(c)

both (a) and (b)

(d)

None of these

12. Which one of the following exhibits highest oxidation state?

(a)

Ni

(b)

Mn

(c)

V

(d)

Zr

13. Which of the following statement is correct for 3d-transition element?

(a)

All metals except Zn and Sc form 'MO' Oxide

(b)

All metals except Sc forms 'MO' Oxide

(c)

All metals except Zn forms 'MO' Oxide

(d)

All metals except Mn forms 'MO' Oxide

14. Except ______________ all element from Rf to Cn, are synthetically prepared and have very low half life periods.

(a)

(b)

actinium

(c)

yttrium

(d)

15. A mixture of TiCl4 and trialkyl aluminium is _________

(a)

hydroformylation of obfine

(b)

Zeigler - Natta Catalyst

(c)

interstitial compounds

(d)

ferromagnetic

16. 2 Marks

10 x 2 = 20
17. What are transition metals? Give four examples.

18. Justify the position of lanthanides and actinides in the periodic table.

19. Why Gd3+ is colourles?

20. complete the following.
a. MnO42- + H+ ⟶|?
b. C6H5CH3 $\overset { acidified }{ \underset { KMnO_{ 4 } }{ \longrightarrow } }$?
c. MnO4- + Fe2+ ⟶?
d. KMnO4 $\overset { \triangle }{ \underset { Red\quad hot }{ \longrightarrow } }$ ?
e. Cr2O72- + I- + H+ ⟶?
f. Na2Cr2O7 + KCl ⟶?

21. What are coinage metals?

22. Which is the most common oxidation state of lanthanoides?

23. Calculate the magnetic moment of Fe3+ ion (Atomic no. of Fe = 26)

24. Arrange the following in increasing order of acidic character?
CrO3, CrO, Cr2O3

25. What is an alloy? Give an example.

26. What are the conditions for alloy formation?

27. 3 Marks

10 x 3 = 30
28. Complete the following equations.
(i) Cr2O72- + 2OH-
(ii) MnO4- + 4H+ + 3e- ⟶

29. Account for the following:
(i) Cobalt (II) is stable in aqueous solution but in the presence of complexing reagents, it is easily oxidised.
(ii) The d1 configuration is very unstable in ions.

30. Give reason for the following:
(i) A transition metal exhibits highest oxidation state in oxides and fluorides.
(ii) Cu2+ is unstable in an aqueous solution.

31. Complete the following reactions?
i) Cr2 + 2e-
ii) Mn2+ + 2e- ⟶
iii) Fe2+ + 2e
iv) CO2+ + 2e-

32. Write the properties of interstitial compound.

33. What is chromyl chloride test? Give equations.

34. Explain the preparation of potassium permanganate from pyrolusite.

35. Explain the oxidising property of KMnO4 in natural medium. Give the equations.

36. Why Hcl and HNO3 cannot be used for making the KMnO4 medium acidic?

37. 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.

38. 5 Marks

7 x 5 = 35
39. Out of Lu(OH)3 and La(OH)3 which is more basic and why?

40. Which is stronger reducing agent Cr2+ or Fe2+?

41. Transition metals show high melting points why?

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

43. Why is there a variation of atomic andionic size as we move from Sc to Zn?

44. How are materials classified based on their magnetic properties?

45. Complete the following reactions
(i) Cr2O72-
(ii) Cr2O7- + 6I-+ 14H+ ⟶
(iii)  Cr2O7- + 3S2-+ 14H+ ⟶
(iv) Cr2O7- + 3SO2+ 14H+
(v) Cr2O7- +3Sn2+ + 14H+ ⟶
(vi) K2Cr2O7 + 8H2SO4 + 3CH3CH2OH ⟶
(vii) 2MnO4- + 5(COO)2- + 6H+ ⟶
(viii) 2MnO4- + 10I+ 16H+
(ix) 2MnO4- + 5S2-+ 16H+ ⟶
(x) 2MnO4- + 5NO2- + 6H+ ⟶
(xi) 2KMnO4 + 3H2SO4 + 5CH3CH2OH ⟶
(xii) 2MnO4- + 5SO32- + 6H+