Question

A solution of a substance X is used for while washing.
d) Name the substance X and write its formula.
(i) Write the reaction of the substance X named in (i) above withwater​

Answer 1

AnswEr:

(i) The Substance 'X' Which is used in White Washing is Calcium Oxide.

Formula of Calcium Oxide is (CaO).

(ii) Calcium Oxide Reacts with water to produce Slaked Lime. [Ca(OH)2]

$\sf\: CaO + H_2O \longrightarrow\: Ca(OH)_{2} (aq)$

This is the example of combination Reaction.

Combination Reaction is the Reaction in which two substance combines together and form single substance.

$\rule{150}3$

Calcium Oxide or Quick Lime is used For white Washing, When Calcium oxide reacts with water forms Calcium Hydroxide & from Atmosphere it absorbs Carbon dioxide & Forms Calcium carbonate.

$\rule{150}3$

Answer 2

i) The substance used for white washing is CaO (Calcium Oxide)

Therefore, substance X is Calcium oxide having formula CaO.

ii) Now we have to write the reaction of substance X i.e. of Calcium oxide with water.

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

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

When Calcium oxide reacts with water then the formation of Calcium hydroxide takes place.

Another name of Calcium hydroxide is Slaked lime.

If Slaked lime reacts with carbon dioxide then the formation of Calcium carbonate takes place, which is an example of Double Displacement Reaction.