Page 1 - Microsoft Word - Lesson note-3(d-block element )

SUBJECT-CHEMISTRY

CHAPTER-D-BLOCK ELEMENT

SUBTOPIC- Preparation and properties of K2Cr2O7 and KMnO4.

KEY NOTES:

K Cr O
2 7
2
Preparation:
4FeCr O  8Na CO  7O  8Na CrO  2Fe O  8 CO
2
4
2
4
2
3
2
2 3
2
2Na CrO  H SO  Na CrO  Na SO  H O
4
2
2
4
2
2
7
4
2
Na Cr O  2KCl K Cr O  2NaCl
2
2
2
7
7
2
Structure:

Chemical properties:


(i) Cr O 2  14H  6I  2Cr 3  3I  7H O
2 7
2
2



(ii) Cr O 2  3H S 8H  2Cr 3  3S 7H O
2
2 7
2
4
2


(iii) Cr O 2  3Sn  14H  2Cr 3  7H O 3Sn
2
2 7
3


(iv) Cr O 2  6Fe 2  14H  2Cr 3  7H O 6Fe
2 7
2
KMnO
4
Preparation:

(i) 2MnO  4KOH O  2K MnO  2H O
2
4
2
2
2


4H  3MnO  2MnO  MnO  2H O
2
2
2
4


(ii) 2Mn 2  5S O 2  8H O 2MnO  10 SO 2  16H
4
2 8
4
2
It is dark purple coloured crystalline solid.
 Chemical properties
(i) MnO  5Fe 2  8H  5Fe 3  Mn 2  4H O


4
2


(ii) 2MnO  16H  5C O 2  2Mn 2  8H O 10CO

2
4
2
2 4



(iii) 2MnO  10I  16H  2Mn 2  5I  8H O
2
4
2



2


(iv) 2MnO  5NO  6H  5NO  3H O 2Mn
3
2
2
4




(v) 2MnO  5H S 6H  2Mn 2  8H O 5S
4
2
2


2
(vi) 2MnO  5SO 2  6H  2Mn 2  3H O 5SO

3
2
4
4

(vii) 2KMnO  K MnO  MnO 
O
4
2
2
2
4
(viii) 2MnO  H O I  2MnO  2OH  IO





3
4
2
2


(ix) 8MnO  3S O 2  H O  8MnO  6 SO 2  2OH
2
4
4
2 3
2