Isolation of Metals

1

During the process of electrolytic refining of copper, some metals present as impurity settle as 'anode mud'. These are

  1. Ag and Au
  2. Sn and Ag
  3. Fe and Ni
  4. Pb and Zn
2

In the context of the Hall-Heroult process for the extraction of Al, which of the following statements is false?

  1. Al2O3 is mixed with CaF2 which lowers the melting point of the mixture and brings conductivity
  2. Al3+ is reduced at the cathode to form Al
  3. Na3AlF6 serves as the electrolyte
  4. CO and CO2 are produced in this process
3

Aluminium is extracted by the electrolysis of

  1. bauxite
  2. molten cryolite
  3. alumina mixed with molten cryolite
  4. alumina
4

Cyanide process is used for the extraction of

  1. barium
  2. aluminium
  3. silver
  4. boron
5

Which one of the following ores is best concentrated by froth ­flotation method?

  1. Cassiterite
  2. Malachite
  3. Magnetite
  4. Galena