Name the metal which is extracted from the ore called 'Rock salt'
(b) Name two ores of zinc. Write the names of the chemical compounds present in them and give their chemical formulae.
(c) Explain how, mercury is extracted from its sulphide ore (cinnabar). Give equation of the reactions involved.
(d) In the electrolytic refining of a metal M, what would you tak eas anode, cathode and electrolyte?
(e) Name any five metals which are purified by electrolytic refining method.
Name the metal which is extracted from the ore called 'Rock salt'
(b) Name two ores of zinc. Write the names of the chemical compounds present in them and give their chemical formulae.
(c) Explain how, mercury is extracted from its sulphide ore (cinnabar). Give equation of the reactions involved.
(d) In the electrolytic refining of a metal M, what would you tak eas anode, cathode and electrolyte?
(e) Name any five metals which are purified by electrolytic refining method.
ANSWER:
(a) The metal extracted from the ore rock salt is sodium. The sodium compound present in this ore is sodium chloride. The chemical formula of the ore is NaCl.
(b) The two ores of zinc are calamine ore and zinc blende. The chemical compound present in calamine is zinc carbonate (carbonate ore) and its chemical formula is ZnCO3. The chemical compound present in zinc blende is zinc sulphide (sulphide ore) and its chemical formula is ZnS.
(c) Cinnabar is a sulphide ore of mercury. The name of the compound present in the cinnabar ore is mercury (II) sulphide. Its chemical formula is HgS. Mercury is a less reactive metal and it can be extracted from its sulphide ore cinnabar by heating it in air alone.
1. It is first heated in the presence of surplus air (roasting process). This converts mercury (II) sulphide to mercury (II) oxide.
2HgS+3O2Roasting (surplus of air)−−−−−−−−−−−−−−−→2HgO+2SO2
2. Mercury (II) oxide, so formed, is heated to around 300oC and it gets reduced to mercury metal.
22HgOHeating upto 3000C−−−−−−−−−−−−→2Hg+O2
(d) In electrolytic refining of a metal, the electrolytic refining tank consists of:
Anode: A bulky piece of impure metal (attached to positive terminal)
Cathode: A thin layer of pure metal (attached to negative terminal)
Electrolyte: Salt solution of the metal, which is being refined, is taken as the electrolytic solution or electrolyte.
When electricity is passed through the cell, impure metal from the anode melts and goes into the electrolyte. The pure metal from the electrolyte moves to the cathode and gets deposited there as a pure metal. The impurities that are soluble dissolve in the electrolyte and insoluble impurities deposit under the anode as anode mud.
(e) Five metals that can be purified by electrolytic refining method are copper, zinc, chromium, lead and nickel.
ANSWER:
(a) The metal extracted from the ore rock salt is sodium. The sodium compound present in this ore is sodium chloride. The chemical formula of the ore is NaCl.
(b) The two ores of zinc are calamine ore and zinc blende. The chemical compound present in calamine is zinc carbonate (carbonate ore) and its chemical formula is ZnCO3. The chemical compound present in zinc blende is zinc sulphide (sulphide ore) and its chemical formula is ZnS.
(c) Cinnabar is a sulphide ore of mercury. The name of the compound present in the cinnabar ore is mercury (II) sulphide. Its chemical formula is HgS. Mercury is a less reactive metal and it can be extracted from its sulphide ore cinnabar by heating it in air alone.
1. It is first heated in the presence of surplus air (roasting process). This converts mercury (II) sulphide to mercury (II) oxide.
2HgS+3O2Roasting (surplus of air)−−−−−−−−−−−−−−−→2HgO+2SO2
2. Mercury (II) oxide, so formed, is heated to around 300oC and it gets reduced to mercury metal.
22HgOHeating upto 3000C−−−−−−−−−−−−→2Hg+O2
(d) In electrolytic refining of a metal, the electrolytic refining tank consists of:
Anode: A bulky piece of impure metal (attached to positive terminal)
Cathode: A thin layer of pure metal (attached to negative terminal)
Electrolyte: Salt solution of the metal, which is being refined, is taken as the electrolytic solution or electrolyte.
When electricity is passed through the cell, impure metal from the anode melts and goes into the electrolyte. The pure metal from the electrolyte moves to the cathode and gets deposited there as a pure metal. The impurities that are soluble dissolve in the electrolyte and insoluble impurities deposit under the anode as anode mud.
(e) Five metals that can be purified by electrolytic refining method are copper, zinc, chromium, lead and nickel.
