An element A reacts with water to form a compound B which is used


#1

An element A reacts with water to form a compound B which is used in white washing. The compound B on heating forms an oxide C which on , treatment with water gives back B. Identify A,B and C and give the reactions involved.


#2

Element A is calcium (Ca). When it reacts with water, it forms calcium hydroxide. Thus, compound B is calcium hydroxide [Ca(OH)2], which is used in white washing.

Compound B on heating gives CaO.

Thus, C is calcium oxide (CaO).
C(CaO) on treatment with water gives back B [Ca(OH)2].