Chlorine gas reacts with the aromatic ring of lignin to form which of the following substances?

What would have happened if the greenhouse gases were totally missing in the earth's atmosphere? Discuss.

Which of the following is a major air pollutant?

Explain tropospheric pollution caused by oxides of sulphur with suitable examples.

Identify the correct statements from the following:
$i$. In the presence of $UV$ light,$CF_2Cl_2(g)$ gives chlorine free radicals which will react with $O_3(g)$ to form $O_2(g)$.
$ii$. Drinking water with $10 \ ppm$ fluoride is better than drinking water with $1 \ ppm$ fluoride.
$iii$. The maximum permissible concentration of lead in drinking water is $50 \ ppb$.

What is the main source of chlorofluorocarbon $(CFC)$ pollution?