A solid compound `'X'` on heating gives `CO_(2)` gas and a residue. The residue mixed with water forms `'Y'`. On passing an excess of `CO_(2)` through `'Y'` in water , a clear solution, `'Z'` is obtained. On boiling `'Z'`, compound `'X'` is reformed. The compound `'X'` is

A solid compound 'X' on heating gives CO_(2) gas and a residue. The residue mixed with water form 'Y' . On passing an excess of CO_(2) through 'Y' in the water, a clear solution 'Z' is obtained. On boiling 'Z' compound 'X' is reformed. The compound 'X' is :

A solid compound 'X' on heating gives CO_(2) gas and a residue. The residue mixed with water forms 'Y'. On passing an excess of CO_(2) through Y in water, a clear solution 'Z' is obtained. On boiling 'Z' compound 'X' is formed. The compound 'X' is

A solid compound X on heating gives CO_(2) gas and a residue. The residue mixed with water forms Y. On passing excess of CO_(2) through Y in water, a clear solution Z is obtained. On boiling Z, compound X is reformed. The compound X is

A solid compound X on heating gives CO_(2) gas and a residue. When mixed with water it forms Y. On passing excess of CO_(2) through Y in water a clear solution of Z is obtained. On boiling Z compound X is reformed. Compound X is

A compound (A) on heating in Busen flame imparts brick red colouration. (A) on heating gives CO_(2) gas and a residue (B) . The residue (B) when treated with water gives (c ) . On passing an excess of CO_(2) through (C ) in water, a clear solution (D) is obtained. On boiling (D) , compound (A) is reformed. Compound (A) is