Question

The process of calcination and roasting in metallurgical industries, respectively, can lead to
1) Photochemical smog and ozone layer depletion
2) Photochemical smog and global warming
3) Global warming and photochemical smog
4) Global warming and acid rain

Answer 1

Hint: Metallurgy defines the metal extraction process from its ore. To answer this question, we have to understand the process of calcination and roasting in detail. In both these methods, the conversion of ores into oxides takes place.

Complete Step by Step Answer:
Let's first understand the process of roasting. In this process, the heating of ore is done in the presence of an excess amount of air. And this method is used mainly for the conversion of sulphide ores into oxides. In this reaction, production of sulphur dioxide (\[{\rm{S}}{{\rm{O}}_{\rm{2}}}\] ) gas takes place. For example:
\[2{\rm{ZnS}} + 3{{\rm{O}}_{\rm{2}}} \to 2{\rm{ZnO}} + 2{\rm{S}}{{\rm{O}}_{\rm{2}}}\]

Now, we will understand the process of calcination. In this process, the heating of the ore is done in the zero presence of air. This reaction is used in the case of carbonate ores. And the gas released in this process is \[{\rm{C}}{{\rm{O}}_{\rm{2}}}\]. For example:
\[{\rm{ZnC}}{{\rm{O}}_{\rm{3}}} \to {\rm{ZnO}} + {\rm{C}}{{\rm{O}}_{\rm{2}}}\]

Let's understand the phenomenon of global warming and acid rain.
Global warming defines the phenomenon of the increase in the earth's average temperature. This is because of the greenhouse gases such as \[{\rm{C}}{{\rm{O}}_{\rm{2}}}\], \[{\rm{C}}{{\rm{H}}_{\rm{4}}}\] etc. As we understand above that, in the process of calcination, the release of \[{\rm{C}}{{\rm{O}}_{\rm{2}}}\] takes place. Therefore, calcination is responsible for global warming.

Rainwater when composed of acidic components such as nitric acid and sulphuric acid is termed acid. So, roasting is also the reason for causing acid rain.
Therefore, option 4 is right.

Note: The phenomenon of global warming is responsible for climate change and the rise of sea levels due to the melting of ice. Global warming is controlled by planting more and more plants so that carbon dioxide in the atmosphere can be reduced.