While white washing, Ca(OH)2 reacts slowly with CO2 in air to form a thin layer of _____ on the walls.

While white washing, Ca(OH)2 reacts slowly with CO2 in air to form a

1.	While white washing, Ca(OH)2 reacts slowly with CO2 in air to form a thin layer of _____ on the walls.
A.	CaO
B.	CaSO4
C.	CaCl2
D.	CaCO3
Answer» E.