Enzyme catalase decomposes hydrogen peroxide in cells. This enzyme is present in: MCQ with Answer and Explanation

Explanation:
SO₂ (from burning coal) and NOₓ dissolve in rain to form H₂SO₄ and HNO₃. CO is toxic but does not form strong acid; CH₄ is greenhouse gas; ground-level O₃ is secondary pollutant and irritant.

Explanation:
Sulphuric acid is a key reagent in many processes: to produce HCl from NaCl, HNO₃ from nitre, fertilizers (superphosphate), and in petroleum refining, pickling, etc. It is also used as a dehydrating agent and catalyst. Ammonia is made by Haber process without H₂SO₄. NaOH is made by electrolysis of brine. H₂SO₄ is known as 'king of chemicals'.

Explanation:
The amount of dissolved oxygen is crucial for aquatic life. The Biological Oxygen Demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material. High BOD indicates high organic pollution and low dissolved oxygen levels.