An element belongs to group 1 and period 3 reacts with chlorine gas to form A. (A) reacts with ammonium bicarbonate to give compounds (B) and (C). Compound period is beryllium (A). (B) is then heated to give compound (D). Identify A, B, C and D and write the respective equations.

Explanation

(i) An element beonging to group number 1 and period number 3 is sodium.
(ii) Sodium, on reaction with a halogen `(Cl_2)` forms sodium chloride (D).
`2Na+Cl_2tounderset((A))2NaCl`
(iii) sodium chloride reacts with ammonium bicarbonate to give sodium bicarbonate (B) and ammonium chloride (C )
`2NH_4HCO_3underset((A))NaCltounderset((C ))NH_4Cl+underset((B))NaHCO_3`
(iv) sodium bicarbonate on heating forms sodium carbonate (D)
`underset((B))2NaHCO_3tounderset((D))Na_2CO_3+CO_2+H_2O`