The pH of a solution is 4.5. What is the nature of the solution? MCQ with Answer and Explanation

Explanation:
Flooded rice paddies promote anaerobic decomposition of organic matter, producing methane (CH₄). It is a potent greenhouse gas. Livestock also emit methane.

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:
Mass number = protons + neutrons = 6 + 8 = 14. This corresponds to carbon-14 isotope. Atomic number = 6 (carbon).