Exams › JEE Advanced › Chemistry
Find the number of the following reactions that are involved in roasting: i. $\mathrm{S + O_2 \rightarrow SO_2}$ ii. $\mathrm{P_4 + 5O_2 \rightarrow P_4O_{10}}$ iii. $\mathrm{4As + 3O_2 \rightarrow 2As_2O_3}$ iv. $\mathrm{2ZnS + 3O_2 \rightarrow 2ZnO + 2SO_2}$ v. $\mathrm{ZnCO_3 \rightarrow ZnO + CO_2}$
- 2
- 3
- 4
- 5
Correct answer: 4
Solution
Roasting is heating an ore in excess air or oxygen, typically converting sulphides to oxides or releasing volatile oxides. Reactions i, ii, iii, and iv involve oxidation in air, while v is calcination of a carbonate, not roasting.
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