Question

Write the chemical formula for washing soda? How may it be obtained from baking soda? Name an industrial use of washing soda other than washing clothes.

Answer 1

Part-1:

Washing soda:

• The chemical name of washing soda is sodium carbonate.
• It is a white odourless powder.
• The chemical formula of washing soda (sodium carbonate) is ${\mathrm{Na}}_2{\mathrm{CO}}_3$.

Part-2:

Synthesis:

• The washing soda can be obtained from baking soda$\left({\mathrm{NaHCO}}_3\right)$ by Solvay's process.
• Solvay's process is a two-step process
• Where the sodium chloride solution $\left(\mathrm{NaCl}\right)$ is saturated with ammonia gas $\left({\mathrm{NH}}_3\right)$, carbon dioxide $\left({\mathrm{CO}}_2\right)$ and water vapour $\left({\mathrm{H}}_2\mathrm{O}\right)$ and cooled. A precipitate of solid sodium bicarbonate or baking soda (${\mathrm{NaHCO}}_3$) is obtained.

$$\begin{gathered} {\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)+\mathrm{NaCl}\left(\mathrm{aq}\right)+{\mathrm{NH}}_3\left(\mathrm{g}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)\to {\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{aq}\right)+{\mathrm{NaHCO}}_3\left(\mathrm{s}\right) \\ \left(\mathrm{Water}\right)(\mathrm{Sodium}(\mathrm{Ammonia})(\mathrm{Carbon}(\mathrm{Ammonium}(\mathrm{Sodium} \\ \mathrm{chloride})\mathrm{dioxide})\mathrm{chloride})\mathrm{bicarbonate}) \end{gathered}$$

• The above precipitate of baking soda is filtered, dried and ignited to form solid sodium carbonate (${\mathrm{Na}}_2{\mathrm{CO}}_3$).

$$\begin{gathered} 2{\mathrm{NaHCO}}_3\left(\mathrm{s}\right)\to {\mathrm{Na}}_2{\mathrm{CO}}_3\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ (\mathrm{Sodium}(\mathrm{Sodium}(\mathrm{carbon}(\mathrm{water}\left) \\ \mathrm{bicarbonate}\right)\mathrm{carbonate})\mathrm{dioxide}) \end{gathered}$$

Uses:

• It is used in the glass, paper, textile and soap industries.
• It is used as a cleansing agent in industries.
• It is used in the process of softening water.