Question

) Raman uses solution of a substance X for white washing his house. Name the substance X.

a)CaO
b)caCO^3
c)NaCl
d)CuO​

Answer 1

Your answer:

option a

CaO

Answer 2

Answer

a) CaO

$\rule{200}2$

Explanation

The substance used for white washing is CaO (Calcium Oxide). Therefore, the substance X is Calcium oxide having formula CaO.

When Calcium oxide reacts with water, following reaction takes place-

$\sf{CaO+H_2O\rightarrow Ca(OH)_2}$

When Calcium oxide reacts with water formation of Calcium Hydroxide (another name - Slaked lime) having formula Ca(OH)2 takes place.

The above reaction is an example of a Combination Reaction. Because in it two or more reactants combine to form a single product.

Also,

$\sf{Ca(OH)_2+CO_2\rightarrow CaCO_3+H_2O}$

When Calcium Hydroxide reacts with carbon-dioxide formation of Calcium Carbonate takes place.

The above reaction is an example of a Double Displacement Reaction. Because the exchange of ions takes place. Also, known as Precipitation Reaction, as the formation of precipitate takes place.