Explain the role of each of the following:
(i) NaCN in the extraction of silver
(ii) SiO2 in the extraction of copper
(i) Name the method of refining of metals such as Germanium.
(ii)In the extraction of Al, impure Al2O3 is dissolved in conc. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?
(iii)What is the role of coke in the extraction of iron from its oxides?
Describe the principle controlling each of the following processes:
(i) Preparation of cast iron form pig iron.
(ii) Preparation of pure alumina (Al2O3) from bauxite ore.Explain the principle of the method of electrolytic refining of metals. Give one example.
Electrolytic refining; Electrolytic refining is the process of refining impure metals by using electricity. In this process, impure metal is made the anode and a strip of pure metal is made the cathode. A solution of a soluble salt of the same metal is taken as the electrolyte. When an electric current is passed, metal ions from the electrolyte are deposited at the cathode as a pure metal and the impure metal from the anode dissolves into the electrolyte in the form of ions. The impurities present in the impure metal gets collected below the anode. This is known as anode mud.
Copper refined by the electrolytic refining.
Out of PbS and PbCO3 (ores of lead), which one is concentrated by froth flotation process preferably?
Write the chemical reactions involved in the process of extraction of Gold. Explain the role of dilute NaCN and Zn in this process