Some tranquilizers are listed below. Which one from the following belongs to barbiturates?

So₂ is the component of classical smog.

Complete reaction of acid rain is

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

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

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

It is process in which nutrient enriched water bodies support a dense plant population which kills animal life by depriving it of oxygen and result in subsequent loss of biodiversity is known as Eutrophication.