Identify the incorrect statement(s).
- In floatation process, ZnO and SO3 are formed from sulphide ores.
- To prevent corrosion of Zn, Fe is used as coating material.
- Cd metal is used in nuclear reactors as neutron excitation material.
- Mercury is used extensively in the production of sodium hydroxide and chlorine gas commercially.
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1 and 2
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2 and 3
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3 and 4
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1, 2, 3
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2, 3, 4
B
Correct answer
Explanation
- 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 SO2.
- Zn is used extensively for coating for the appliances made up of corrosive metals like Fe to prevent them from rusting.
- Cd metal absorbs neutrons very well, and is used to make control rods in nuclear reactors.
- The largest use of mercury is in electrolytic cells for the production of sodium hydroxide and chlorine gas at commercial level.