Question

 A non-metal A is an important constituent of our food and forms two oxides B and C. Oxide B is toxic whereas C causes global warming.
(a) Identify A, B and C.
(b) To which group of periodic table does A belong? 

Answer 1

(a) Non-metai A is carbon. Its two oxides are carbon monoxide (CO) and carbon dioxide. From these. B is carbon monoxide (CO) as it is toxic while C is carbon dioxide (`CO_(2)`) because it is responsible for global warming. 
(b) Electronic configuration of C is 2, 4 (atomic weight of C = 6). it is present in `14^(th)` group (10 + valence electrons), i.e., IV A of the periodic table.