Question

Write the chemical formula of Washing soda. How is it obtained from Baking soda? Name one industrial use of Washing soda other than washing clothes.

Answer 1

Hint: Washing soda is chemically known as sodium carbonate. Baking soda is chemically known as sodium bicarbonate. Baking soda contains an extra hydrogen atom which can be removed in a chemical process to obtain washing soda.

Complete step-by-step solution:

Let us see some properties of washing soda.

The chemical formula of washing soda is  $ { Na }_{ 2 }{ CO }_{ 3 } $ . It is a white crystalline solid which is often available as a white powder. It is soluble in water and when dissolved in water it renders the solution alkaline.

When we dissolve washing soda in water it dissociates in water to form two ions:  $ { Na }^{ + } $  and  $ { C{ O }_{ 3 } }^{ -2 } $ . On addition of water soda into the water, the water molecule  $ ( { H }_{ 2 }O ) $  also breaks into its constituent ions  $ { H }^{ + } $ and ${ OH }^{ - } $ .

The  $ { Na }^{ + } $  ions attracts the negatively charged  $ { OH }^{ - } $  ions from water to form a strong alkali NaOH while the  $ { C{ O }_{ 3 } }^{ 2- } $  ions attract the positively charged  $ { H }^{ + } $  ions from water to form a weak acid  $ { H }_{ 2 }{ CO }_{ 3 } $ . This process is known as salt hydrolysis or hydrolysis of salt.

As we already know, baking soda is sodium hydrogen carbonate. Its chemical formula is  $ NaH{ CO }_{ 3 } $ . By heating the baking soda strongly, we can obtain washing soda. Sodium hydrogen carbonate on heating gives sodium carbonate, carbon dioxide and water. The reaction is given below.

 $ NaH{ C{ O }_{ 3 } }_{ \left( s \right) }\overset { \triangle }{ \longrightarrow } { Na }_{ 2 }{ C{ O }_{ 3 } }_{ \left( S \right) }+{ C{ O }_{ 2 } }_{ \left( g \right) }\uparrow +{ H }_{ 2 }{ O }_{ \left( g \right) }\uparrow $ 

Apart from cleaning purposes, washing soda is largely used in the manufacturing of paper, glass, rayon, etc.

Note: Don’t confuse baking soda with washing soda. Though their name and formula are very similar they have one tiny difference. Washing soda has no hydrogen atom and it has two atoms of sodium while baking soda has a hydrogen atom and it contains only one sodium atom.

Baking soda:  $ NaHC{O }_{ 3 } $ 

Washing soda:  $ { Na }_{ 2 }{ CO }_{ 3 } $