Name: Reactions of Metal Carbonates with Acids
Uploaded: 2019-07-19
Duration: 4 min 6 s
Description: When substances like metals and liquids like acid react, it produces salt, water, and carbon dioxide. Here, in this video, it has been explained in detail wi...

Question

Describe how washing soda is produced starting from sodium chloride (common salt). Write equations of all the reactions involved.

Accepted Answer

Production of washing soda: Washing soda is produced from brine (sodium chloride $(NaCl)$ ) in the following three steps:
(1) A cold and concentrated solution of brine (sodium chloride) is reacted with ammonia $({NH}_{3})$ and carbon dioxide $({CO}_{2})$ to obtain sodium hydrogen carbonate $({NaHCO}_{3})$ .
The chemical reaction involved in this process is:
$\underset{\begin{matrix} Sodium chloride \\ (Common salt) \end{matrix}}{NaCl} + \underset{Ammonia}{{NH}_{3}} + \underset{water}{H_{2} O} + \underset{\begin{matrix} Carbon \\ dioxide \end{matrix}}{{CO}_{2}} \to \underset{\begin{matrix} Sodium hydrogen \\ carbonate \end{matrix}}{{NaHCO}_{3}} + \underset{\begin{matrix} Ammonium \\ chloride \end{matrix}}{{NH}_{4} Cl}$

(2) Sodium hydrogen carbonate is only slightly soluble in water, so it precipitates out as a solid. Sodium hydrogen carbonate $({NaHCO}_{3})$ is separated by filtration, dried and heated. On heating, sodium hydrogen carbonate $({NaHCO}_{3})$ decomposes to form sodium carbonate $({Na}_{2} {CO}_{3})$ .
The chemical reaction involved in this process is:

$\underset{\begin{matrix} Sodium hydrogen - \\ carbonate \end{matrix}}{2 {NaHCO}_{3}} \overset{Heat}{\to} \underset{\begin{matrix} Sodium carbonate \\ (soda ash) \end{matrix}}{{Na}_{2} {CO}_{3}} + \underset{\begin{matrix} Carbon \\ dioxide \end{matrix}}{{CO}_{2}} + \underset{Water}{H_{2} O}$

(3) The anhydrous sodium carbonate obtained is dissolved in water and recrystallised to get washing soda crystals containing 10 molecules of water of crystallisation and form sodium carbonate decahydrate (washing soda).

The chemical reaction involved in this process is:
$\underset{\begin{matrix} Anhydrous sodium carbonate \\ (Soda ash) \end{matrix}}{{Na}_{2} {CO}_{3}} + \underset{Water}{10 H_{2} O} \to \underset{Sodium carbonate decahydrate}{{Na}_{2} {CO}_{3} . 10 H_{2} O}$

Describe how washing soda is produced starting from sodium chloride (common salt). Write equations of all the reactions involved.

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