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Metallic gold frequently is found in aluminosilicate rocks and its is finely dispersed among other minerals. It may be extracted by trating the crushed rock with aerated potassium cyanide solution. During this process metallic gold is slowly converted to [Au(CN)2 ] – , which is soluble in water. After equilibrium has been reached, the aqueous phase is pumped off and the metallic gold is recovered from it by reacting the gold complex with zinc, which is converted to [Zn(CN)4 ] 2–. Gold in nature is frequently alloyed with silver which is also oxidised by aerated sodium cyanide solution. Silver occurs as native as well as sulphurised ore.
The correct reaction involved in the leaching of gold with dilute solution of NaCN is :
The correct answer is:
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chemistry-
Minerals from which metals can be extracted economically and easily are called ores. The extraction of metals from theirs ores involves the following processes.
i) Concentration
ii) Calcination | roasting | leaching
iii) Reduction It is carried out by one of the following methods.
Minerals from which metals can be extracted economically and easily are called ores. The extraction of metals from theirs ores involves the following processes.
i) Concentration
ii) Calcination | roasting | leaching
iii) Reduction It is carried out by one of the following methods.
chemistry-General
chemistry-
The chemical composition of “slag” formed during the smelting process in the extraction of copper is :
The chemical composition of “slag” formed during the smelting process in the extraction of copper is :
chemistry-General
chemistry-
Native silver metal forms a water soluble complex with a dilute aqueous solution of NaCN in the presence of:
Native silver metal forms a water soluble complex with a dilute aqueous solution of NaCN in the presence of:
chemistry-General
chemistry-
Dow's process of extraction of Mg involves extraction of Mg from sea water. Sea water is concentrated in sun light and is then treated with slaked lime. Magnesium hydroxide is heated in a stream of HCl to give MgCl2 which is electrolysed to discharge Mg. The mixture is in the ratio 
are added to lower the fusion temperature and to increase the conductance.
Electrolysis of fused MgCl2 
electrolysed is protected from atmospheric oxidation by a blanket of inert gases
In the hydrated chloride of Mg the value of of x is
Dow's process of extraction of Mg involves extraction of Mg from sea water. Sea water is concentrated in sun light and is then treated with slaked lime. Magnesium hydroxide is heated in a stream of HCl to give MgCl2 which is electrolysed to discharge Mg. The mixture is in the ratio are added to lower the fusion temperature and to increase the conductance.
Electrolysis of fused MgCl2
electrolysed is protected from atmospheric oxidation by a blanket of inert gases
In the hydrated chloride of Mg the value of of x is
chemistry-General
chemistry-
Dow's process of extraction of Mg involves extraction of Mg from sea water. Sea water is concentrated in sun light and is then treated with slaked lime. Magnesium hydroxide is heated in a stream of HCl to give MgCl2 which is electrolysed to discharge Mg. The mixture is in the ratio are added to lower the fusion temperature and to increase the conductance.
Electrolysis of fused MgCl2 
electrolysed is protected from atmospheric oxidation by a blanket of inert gases.
2 This reaction indicates :
Dow's process of extraction of Mg involves extraction of Mg from sea water. Sea water is concentrated in sun light and is then treated with slaked lime. Magnesium hydroxide is heated in a stream of HCl to give MgCl2 which is electrolysed to discharge Mg. The mixture is in the ratio are added to lower the fusion temperature and to increase the conductance.
Electrolysis of fused MgCl2
electrolysed is protected from atmospheric oxidation by a blanket of inert gases.
2 This reaction indicates :
chemistry-General
chemistry-
Extraction of Aluminium can be understand by : 
electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite) .
Cathode : Graphite inside the Fe container
Anode : Graphite rods
What is wrong if anode is made of nickel instead of graphite?
Extraction of Aluminium can be understand by : electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite) .
Cathode : Graphite inside the Fe container
Anode : Graphite rods
What is wrong if anode is made of nickel instead of graphite?
chemistry-General
chemistry-
Extraction of Aluminium can be understand by : 
electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite) .
Cathode : Graphite inside the Fe container
Anode : Graphite rods
The molten electrolytes contains 
but only Al gets deposited at cathode because :
Extraction of Aluminium can be understand by : electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite) .
Cathode : Graphite inside the Fe container
Anode : Graphite rods
The molten electrolytes contains but only Al gets deposited at cathode because :
chemistry-General
chemistry-
Extraction of Aluminium can be understand by : 
electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite) .
Cathode : Graphite inside the Fe container
Anode : Graphite rods
The function of fluorspar (CaF2) is :
Extraction of Aluminium can be understand by : electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite) .
Cathode : Graphite inside the Fe container
Anode : Graphite rods
The function of fluorspar (CaF2) is :
chemistry-General
chemistry-
Extraction of Aluminium can be understand by : 
electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite)
Cathode : Graphite inside the Fe container
Anode : Graphite rods
Coke powder is spreaded over the molten electrolyte due to :
Extraction of Aluminium can be understand by : electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite)
Cathode : Graphite inside the Fe container
Anode : Graphite rods
Coke powder is spreaded over the molten electrolyte due to :
chemistry-General
chemistry-
Extraction of Aluminium can be understand by : 
electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite) .
Cathode : Graphite inside the Fe container
Anode : Graphite rods
The purpose of adding cryolite is :
Extraction of Aluminium can be understand by : electrolytic reduction of Al2O3
Electrolyte : (Al2O3 + Cryolite) .
Cathode : Graphite inside the Fe container
Anode : Graphite rods
The purpose of adding cryolite is :
chemistry-General
chemistry-
Which of the following statement is true ?
Which of the following statement is true ?
chemistry-General
chemistry-
To make the following reduction process spontaneous, temperature should be : 
To make the following reduction process spontaneous, temperature should be :
chemistry-General
chemistry-
chemistry-General
chemistry-
Metallic gold frequently is found in aluminosilicate rocks and it is finely dispersed among other minerals. It may be extracted by treating the crushed rock with aerated sodium cyanide solution. During this process metallic gold is slowly converted to 
, which is soluble in water. After equilibrium has been reached, the aqueous phase is pumped off and the metallic gold is recovered from it by reacting the gold complex with zinc, which is converted to 
Gold in nature is frequently alloyed with silver which is also oxidised by aerated sodium cyanide solution.
There have been several efforts to develop alternative gold extraction processes which could replace this one. Why ?
Metallic gold frequently is found in aluminosilicate rocks and it is finely dispersed among other minerals. It may be extracted by treating the crushed rock with aerated sodium cyanide solution. During this process metallic gold is slowly converted to , which is soluble in water. After equilibrium has been reached, the aqueous phase is pumped off and the metallic gold is recovered from it by reacting the gold complex with zinc, which is converted to Gold in nature is frequently alloyed with silver which is also oxidised by aerated sodium cyanide solution.
There have been several efforts to develop alternative gold extraction processes which could replace this one. Why ?
chemistry-General
chemistry-
Statement-1 :Lead, tin and bismuth are purified by liquation method.
Statement-2 : Lead, tin and bismuth have low m.p. as compared to impurities
Statement-1 :Lead, tin and bismuth are purified by liquation method.
Statement-2 : Lead, tin and bismuth have low m.p. as compared to impurities
chemistry-General
