Page 204 - Chemistry ICSE Class X

190 ICSE Chemistry – 10

What is distillation method for refining metals
The more volatile metals such as mercury and zinc CTG RWTKſGF D[
distillation method. In this method, the impure metal is heated in a retort.
The pure metal distills over and the impurities are left behind.

What is electrolytic refining method
/QUV OGVCNU XK\ EQRRGT CNWOKPKWO EJTQOKWO UKNXGT GVE CTG TGſPGF D[
electrolytic method. In this method,
ƒ A thick block of impure metal acts as anode. It is connected to the +ve
terminal of the battery.
ƒ A thin sheet of pure metal acts as cathode. It is connected to the –ve
terminal of the battery.
ƒ An aqueous solution of a suitable salt of the metal is used as the
Fig. 7.7 An experimental set-up for electrolytic
UH¿QLQJ RI PHWDOV electrolyte.
#P GZRGTKOGPVCN UGV WR WUGF HQT VJG GNGEVTQN[VKE TGſPKPI QH C OGVCN KU
shown in Fig. 7.7.
On passing current through the electrolyte, pure metal gets deposited
on the cathode, and the impure metal of the anode dissolves. The impurities
either dissolve in the solution or fall below the anode as anode mud.

ASSIGNMENT 3

Occurrence of metals, minerals and ores, Metallurgical operations,
Extraction of metals based on their position in the activity series
ϭ͘ tŚĂƚ ŝƐ ŇƵdž͍ 'ŝǀĞ ŽŶĞ ĞdžĂŵƉůĞ͘
Ϯ͘ EĂŵĞ ŽŶĞ ŽƌĞ ŽĨ ůĞĂĚ ĂŶĚ ŐŝǀĞ ŝƚƐ ĐŽŵƉŽƐŝƟŽŶ͘
ϯ͘ EĂŵĞ ;ĂͿ ĂŶ ŽdžŝĚĞ ŽƌĞ ŽĨ ĂůƵŵŝŶŝƵŵ͕ ;ďͿ ĂŶ ŽdžŝĚĞ ŽƌĞ ŽĨ ŝƌŽŶ͘
ϰ͘ EĂŵĞ ƚŚĞ ŵĞƚĂůƐ ĞdžƚƌĂĐƚĞĚ ĨƌŽŵ ;ĂͿ ĐĂůĂŵŝŶĞ͕ ;ďͿ ĐƵƉƌŝƚĞ͘
ϱ͘ tƌŝƚĞ Ă ĐŚĞŵŝĐĂů ĞƋƵĂƟŽŶ ƐŚŽǁŝŶŐ ƚŚĂƚ ĂůƵŵŝŶŝƵŵ ŚĂƐ ŵŽƌĞ ĂĸŶŝƚLJ ƚŚĂŶ ŝƌŽŶ ĨŽƌ ŽdžLJŐĞŶ͘
ϲ͘ džƉůĂŝŶ ǁŚLJ ĐĂůĐŝƵŵ ĚŽĞƐ ŶŽƚ ŽĐĐƵƌ ĨƌĞĞ ŝŶ ŶĂƚƵƌĞ͘
ϳ͘ dŚĞ ŽdžŝĚĞ y O ŝƐ ƵŶĂīĞĐƚĞĚ ďLJ ǁĂƚĞƌ͘ KƵƚůŝŶĞ Ă ŵĞƚŚŽĚ ďLJ ǁŚŝĐŚ Ă ƐĂŵƉůĞ ŽĨ ƚŚĞ ŵĞƚĂů y ĐĂŶ ďĞ ŽďƚĂŝŶĞĚ ĨƌŽŵ ŝƚƐ ŽƌĞ͘
Ϯ ϯ
'ŝǀĞ ŽŶĞ ƌĞĂƐŽŶ ĂƐ ƚŽ ǁŚLJ LJŽƵ ŚĂǀĞ ĐŚŽƐĞŶ ƚŚĞ ŵĞƚŚŽĚ͘
ϴ͘ KŶ ƚŚĞ ďĂƐŝƐ ŽĨ ƌĞĂĐƟǀŝƚLJ ƐĞƌŝĞƐ͕ ŶĂŵĞ ƚŚĞ ŵĞƚŚŽĚ ƵƐĞĚ ĨŽƌ ƚŚĞ ĞdžƚƌĂĐƟŽŶ ŽĨ ŵĞƚĂů
;ĂͿ ǁŝƚŚ ǀĞƌLJ ůŽǁ ƌĞĂĐƟǀŝƚLJ
;ďͿ ǁŝƚŚ ůŽǁ ƌĞĂĐƟǀŝƚLJ
;ĐͿ ǁŝƚŚ ŵŽĚĞƌĂƚĞ ƌĞĂĐƟǀŝƚLJ
;ĚͿ ǁŝƚŚ ŚŝŐŚ ƌĞĂĐƟǀŝƚLJ

Extraction of Aluminium

Symbol Al Atomic number 13

'NGEVTQPKE EQPſIWTCVKQP K L M Atomic mass 27 u
2, 8 3
#NWOKPKWO YCU ſTUV KUQNCVGF D[ Wohler in 1827. Aluminium could not
be put to much use in the beginning because of its high cost of production.
However, with the development of electrolytic method for the extraction