3.c) The process in (b) produces sulfur dioxide (SO₂), which is a major air pollutant. This can lead to acid rain, causing damage to vegetation, aquatic life, and infrastructure.

3.c) The process in (b) produces sulfur dioxide ($\text{SO}_2$), which is a major air pollutant. This can lead to acid rain, causing damage to vegetation, aquatic life, and infrastructure.

3.d) One use of copper metal is for electrical wiring due to its excellent electrical conductivity and ductility.

4.a) Identify:

i) Gas P: Carbon dioxide ($\text{CO}_2$)

ii) Solid Q: Coke (Carbon)

iii) Solid R: Coke (Carbon)

4.b) The main ore used during the extraction of iron is hematite ($\text{Fe}_2\text{O}_3$).

4.c) One