An element(A) reacts quickly with water liberating a coloulress, odourless gas and a solution of ‘B’. 
Passing  $C{O}_2$ gas through ‘B’ yields a white precipitate ‘Y’ which dissolves on passing excess $C{O}_2$ gas.
Precipitate ‘Y’ effervesced with dilute HCl and gave a brick red colouration to a Bunsen burner flame.
Heating ‘Y’ gave a caustic white compound ‘D’(as one of the product) which when further heated with carbon at ${1000}^{0}C$, gave a solid ‘E’(as one of the product) of immense commercial importance.