Environmental chemistry

Depletion of ozone is due to CF₂Cl₂

The maximum prescribed concentration of manganese in drinking water is 0.05 ppm.

Complete reaction of acid rain is

$2S{O}_2+O_2+2H_{2}O\stackrel{}{\to }2H_{2}S{O}_4\left(acidrain\right)$  

HOCl produce in the stratospheric cloud, by the hydrolysis reaction of ClONO₂.

$ClON{O}_{2\left(g\right)}+H_2{O}_{\left(g\right)}\to HOC{l}_{\left(g\right)}+HN{O}_{3\left(vap\right)}$

Peroxyacetyl nitrate is a secondary air pollutant    

 Photochemical smog has high concentration of oxidising agent like ${\mathrm{N}\mathrm{O}}_2$ ${}_{}$ and ${}_{}$ ${\mathrm{O}}_3$ and is therefore called as oxidising agent.

BOD value less than 5ppm is considered as clean water and BOD value more than 10ppm is considered as polluted water.

As 500g of tooth-paste has = 0.2g of F?
So, 10 g of toothpaste has = (0.2g * 10? g) / 500g F = 400g of F
Hence, concentration in ppm is 400.

Methane gas is produced during anaerobic degradation of vegetation that leads to global warming so considered as greenhouse gas like CO₂. Also it causes cancer.

BOD is the amount of oxygen required by bacteria to break down the organic matter present in a certain volume of sample of water.