When a metal is added to dilute HCl solution, there is no evolution of gas. Metal is
  • \(Zn\)
  • \(Ag\)
  • \(K\)
  • \(Na\)
Heating of concentrated ore in absence of air for conversion in oxide ore in known as
  • none of these
  • Calcination
  • reduction
  • roasting
Which of the following conditions are necessary for rusting of iron?
  • Presence of water only
  • Presence of air only
  • Presence of water and air both
  • None of these
Which of the following methods is used in the concentration of haematite ore?
  • none of these
  • Hydraulic washing
  • Magnetic separation
  • Froth floatation process
Which of the following methods is suitable for preventing an iron vessel from rusting?
  • Applying grease
  • Applying paint
  • Applying a coating of zinc
  • All the above
Physical nature of most of the ionic compounds is
  • liquid
  • May exist in any state
  • solid
  • gas
Removal of impurities from ore is known as
  • Minerals
  • concentration of ore
  • Crushing and grinding
  • gangue
Ionic bond is formed between
  • Two electro-positive elements
  • Electropositive and electronegative elements
  • Two electro-negative elements
  • None of these
Which of the following methods is not used in purification of metals?
  • Liquation
  • Distillation
  • None of these
  • Calcination
\(Zn+xHCl\rightarrow ZnCl_2+Z\) In above equation \(A\) and \(x\) are
  • \(Cl_2,1\)
  • \(H_2,2\)
  • \(H_2,4\)
  • \(H_2,3\)
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