Chemistry - Elements, Their Occurrence and Extraction

Question - 1

The Most abundant element in  the earth's crust is

  • A H2
  • B O2
  • C Si
  • D C

Question - 2

In the froth floatation process for the purification of ores, the ore particles float because

  • A they are light
  • B their surface is not easily wetted by water 
  • C they bear electrostatic charge
  • D they are insoluble

Question - 3

The slamg obtained during the extraction of copper from copper pyrites is composed mainly of

  • A Cu2S
  • B CuSiO3
  • C FeSiO3
  • D SiO2

Question - 4

One of the iron has the composition Fe3O4; its name is

  • A Heaematie
  • B Limonite
  • C Magnetic
  • D Sideric

Question - 5

Which of the following types of metals is expected to occur in native state?

  • A Alkali metals
  • B Alkaline earth metals
  • C Noble metals
  • D Rare earth metals

Question - 6

Which one of the following metals occur chiefly as Oxide in nature?

  • A Zinc
  • B Aluminium
  • C Copper
  • D Lead

Question - 7

The ore Which is concentrated by froth-floatation process is

  • A an Oxide ore
  • B a sulphate ore
  • C a carbonate ore
  • D a sulphide ore

Question - 8

Chemical leaching is useful in the concentration of

  • A Copper Pyrites
  • B bauxite
  • C Cassiterite
  • D galena

Question - 9

Carbon cannot be used in the reduction of Al2O3 because

  • A it is an expensive proposition
  • B the enthalpy of formation of CO2 is more than that of Al2O3
  • C pure carbon is not easily available
  • D the enthalpy of formatin of Al2O3 is too high

Question - 10

In which of the following isolation no reducing agent is required?

  • A Iron from haematite
  • B Aluminium from bauxite
  • C Mercury from cinnabar
  • D Zinc from Zinc blende