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

12th Standard

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Chemistry

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

Multiple Choice Questions

15 x 1 = 15
1. 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

2. 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

3. 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+

4. 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

5. MnO4- react with Br- in alkaline PH to give

(a)

BrO3- MnO2

(b)

Br2, MnO42-

(c)

Br2, MnO2

(d)

BrO-, MnO42-

6. 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.

7. The most common oxidation state of actinoids is

(a)

+2

(b)

+3

(c)

+4

(d)

+6

8. Most of the transition metal ions are coloured, because of the

(a)

presence of unpaired electrons

(b)

energy gap between two energy levels is very small

(c)

both (a) and (b)

(d)

neither (a) nor (b)

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

(a)

Ni

(b)

Mn

(c)

V

(d)

Zr

10. Which of the following is not coloured?

(a)

Mn2+

(b)

Zn2+

(c)

Cr3+

(d)

Cu2+

11. Value of magnetic moment of a divalent metal ion is, 5.92 BM. Total number of electron in its atom would be ______________

(a)

24

(b)

25

(c)

26

(d)

27

12. In black and white photography, the developed film is fixed by washing with ____________

(a)

Hypo solution

(b)

AgBr solution

(c)

Na2S4O6 solution

(d)

FeC2O4 solution

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

(a)

(b)

actinium

(c)

yttrium

(d)

14. The electronic configuration of Sc is _____________

(a)

[Ar] 3d1 4s2

(b)

[Ar] 3d2 4S1

(c)

[Ar] 3d5 4S1

(d)

[Ar] 3d3 4S1

15. Of these statement, which statement is incorrect in most of the transition elements are _____________

(a)

hexagonal close packed

(b)

cubic close packed

(c)

face centered cubic

(d)

symmetrical distribution

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. Explain why compounds of Cu2+ are coloured but those of Zn2+ are colourless.

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

21. Write the electronic configuration of the element with atomic number 102.

22. Why lanthanoids are called f block elements?

23. Comparing La(OH)3 and Lu(OH)3, which is more basic and explain why?

24. Orange colour of Cr2O72- ion charges to yellow in alkali and yellow solution turns out orange on adding H+ ions. Explain why?

25. What is an alloy? Give an example.

26. Write the equation for the action of heat on KMnO4

27. 3 Marks

10 x 3 = 30
28. Explain briefly how +2 states becomes more and more stable in the first half of the first row transition elements with increasing atomic number.

29. Explain the variation in E0M3+/M2+  3d series.

30. Compare lanthanides and actinides.

31. Actinoid contraction is greater from element to element than the lanthanoid contraction, why?

32. Discuss the general characteristic of the 3d series of the transition elements with special reference to their
(i) Atomic size
(ii) Enthalpies of atomisation

33. Explain why oxidation states of transition elements increases first from Sc to Mn and then decrease?

34. 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.

35. What are redox reactions?

36. What is chromyl chloride test? Give equations.

37. Give three uses of KMnO4

38. 5 Marks

7 x 5 = 35
39. Which is stronger reducing agent Cr2+ or Fe2+?

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

41. Why first ionization enthalpy of chromium is lower than that of zinc?

42. Transition metals show high melting points why?

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

44. Write a note on the ionization enthalpy of transition elements.

45. Complete the following reactions
(i) Cr2O72-
(ii) Cr2O72- + 6I-+ 14H+ ⟶
(iii)  Cr2O72-+ 3S2-+ 14H+ ⟶
(iv) Cr2O72- + 3SO+ 2H+
(v) Cr2O72- + 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+