The solution used for white washing of the wall is quick lime(CaO).And when this quick lime is mixed with water it gets converted into slaked lime [Ca(OH)2]
and on exposure to the air it finally gets converted into Calcium carbonate[CaCO3] due to which walls shine...

1.CaO + H2O -----> Ca(OH)2
2.Ca(OH)2 + CO2 -----> CaCO3

Calcium Carbonate and Shiny Finish to Walls

Calcium carbonate is a chemical compound with the chemical formula CaCO3. It is a common substance found in rocks as the minerals calcite and aragonite. It is also the main component of pearls and the shells of marine organisms, snails, and eggs.

Calcium carbonate is widely used in construction as a building material for making cement, mortar, and concrete. It is also used as a filler material in paints, coatings, and plastics.

Shiny Finish on Walls

The shiny finish on walls is often achieved by using a type of paint called gloss paint. Gloss paint contains a higher proportion of resin and pigment than other types of paint, which gives it a shiny and reflective finish.

Calcium carbonate is sometimes added to gloss paint to improve its properties. It can act as a filler to increase the volume of the paint and reduce its cost. It can also provide a smoother and more even finish to the paint.

When calcium carbonate is added to gloss paint, it can help to improve the paint's durability and resistance to moisture and stains. It can also improve the paint's adhesion to the surface and prevent it from peeling or flaking.

In conclusion, while calcium carbonate is not the sole reason for the shiny finish on walls, it can be used as an additive in gloss paint to improve its properties and contribute to the overall appearance of the painted surface.