Question

Zinc blende when roasted in air gives off a gas which if allowed to escape would constitute on atmospheric pollutant. What is the gas?

Answer 1

• Zinc blende$\left(\mathrm{ZnS}\right)$ on roasting in the air reacts with oxygen and gives sulfur dioxide and zinc oxide.
• $$\begin{gathered} 2\mathrm{ZnS}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{ZnO}\left(\mathrm{s}\right)+2{\mathrm{SO}}_2\left(\mathrm{g}\right) \\ (\mathrm{Zinc}(\mathrm{Oxygen})(\mathrm{Zinc}\left(\mathrm{Sulfur} \\ \mathrm{sulphide}\right)\mathrm{oxide})\mathrm{dioxide}) \end{gathered}$$
• Sulfur dioxide gas which is produced is an atmospheric pollutant and is responsible for acid rain.