Multiple choice

Which of the following statements are incorrect?

  1. In floatation process, ZnO and SO3 are formed from sulphide ores.
  2. To prevent corrosion of Zn, Fe is used as a coating material.
  3. Cd metal is used in nuclear reactors as neutron excitation material.
  4. Mercury is used extensively in the production of sodium hydroxide and chlorine gas commercially.

  1. 1 and 2

  2. 2 and 3

  3. 3 and 4

  4. 1, 2 and 3

  5. 2, 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  1. The floatation process is the concentration method of sulphide ores. Zinc ores, mainly ZnS, are concentrated by floatation method, then roasted in air to give ZnO and SO3.
    1. Zn is used extensively for coating for the appliances made up of corrosive metals like Fe to prevent them from rusting.
    2. Cd metal absorbs neutrons very well and is used to make control rods in nuclear reactors.
    3. The largest use of mercury is in electrolytic cells for the production of sodium hydroxide and chlorine gas at commercial level. Hence, statements 2 and 3 are incorrect.

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