Question

Explain about washing soda.

Answer 1

Answer:

Sodium carbonate, Na2CO3, (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, water-soluble salts. All forms have a strongly alkaline taste and give moderately alkaline solutions in water. Historically it was extracted from the ashes of plants growing in sodium-rich soils. Because the ashes of these sodium-rich plants were noticeably different from ashes of wood (once used to produce potash), sodium carbonate became known as "soda ash".[12] It is produced in large quantities from sodium chloride and limestone by the Solvay process.

Explanation:

Answer 2

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➡️Washing soda is also known as sodium carbonate decahydrate.

➡️Formula - Na2CO3.10H2O

${ \red{ \underline{ \bold{Production \: of \: Washing \: Soda - }}}}$

1. A cold and concentrated solution of sodium chloride (called brine) is reacted with ammonia and carbon dioxide to obtain sodium hydrogecarbonate:

➡️NaCl +NH3 + H2O + CO2 - - - - - - - >NaHCO3 +NH4Cl

Sodium hydrocarbonate formed is only slightly soluble in water, so it precipitates out as a solid.

2. Sodium hydrogecarbonate is separated by filtration, dried and heated. On heating, sodium hydrogecarbonate decomposes to form sodium carbonate :

➡️ 2 NaHCO3 - - - - - - - - - - ->Na2CO3 +CO2 +H2O

The anhydrous sodium carbonate obtained here is called soda ash.

3. Anhydrous sodium carbonate is dissolved in water and recrystallised to get washing soda containing 10 molecules of water of crystallisation :

➡️Na2CO3 + 10H2O - - - - - > Na2CO3.10H2O

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➡️It is a transparent crystalline solid.

➡️It is one of the few metal carbonates which turn soluble in water.

➡️It has cleansing properties.

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➡️ It is used in the manufacture of sodium compound such as borax.

➡️It is used for removing permanent hardness of water.

➡️It is used as a cleansing agent.

➡️It is used in the manufacture of glass, soap and paper.