Which of the following changes take place during roasting? (i) Impurities are removed as their volatile oxides. (ii) Ore is converted into its oxide. (iii) Changes like oxidation, chlorination, etc. take place.

Answer: (i),(ii) and (iii)


Roasting causes chemical changes such as oxidation, chlorination, and so on. Impurities are eliminated by the production of volatile oxides.During roasting, moisture and non-metallic impurities in the form of volatile gases are released. Process of roasting consists of solid-gas thermal reaction which includes oxidation, reduction, sulfation, chlorination and pyro hydrolysis. However, roasting which involves sulphides are a major source of air pollution and the main drawback of this process is that it releases a large amount of metallic as well as toxic and acidic compounds which causes harm to the environment.

An example of roasting is when Zinc sulphide is converted into zinc oxide. 2ZnS + 3O2 —> 2ZnO + 2SO2

Was this answer helpful?


5 (7)


Choose An Option That Best Describes Your Problem

Thank you. Your Feedback will Help us Serve you better.

Leave a Comment

Your Mobile number and Email id will not be published.





App Now