Sodium carbonate

Sodium carbonate is also known as soda ash with the chemical formula Na₂CO₃. It is a white powder or granules which is odorless. You should keep it in a tightly closed container, stored in a cool, dry, ventilated area. In addition, you must protect it against physical damage and isolate from incompatible substances. The substance is stable under ordinary conditions of use and storage. Meanwhile, with the CAS register number 497-19-8, it has the EINECS registry number 207-838-8.

Properties: In ordinary situation, the substance is a white powder, strong electrolyte with density of 2.532 g/cm³, melting point of 851°C. It is easily soluble in water, slight soluble in absolute ethyl alcohol, insoluble in propyl alcohol. This chemical is a weak-acid salt but is alkaline when dissolves in water and causes hydrolysis reaction with water. Sodium carbonate is corrosive and can happen neutralization reaction with acid to produce carbon dioxide. In high temperatre, it can decompose to generate oxidation sodium and carbon dioxide. Sodium carbonate reacts with water can produce Na₂CO₃·10H₂O, Na₂CO₃·7H₂O, Na₂CO₃·H₂O, Na₂CO₃·10H₂O is the most stable of the three hydrates.

Preparation: Sodium carbonate can be extracted from the ashes of many plants. It is synthetically produced in large quantities from table salt and limestone in a process known as the Solvay process. The process needs calcium carbonate which is heated to release carbon dioxide at the bottom of the tower and ammonia used to convert sodium chloride to sodium carbonate at the top of the tower. The sodium bicarbonate was then converted to Sodium carbonate by heating it, releasing water and carbon dioxide:

CaCO₃ → CaO + CO₂
NaCl + NH₃ + CO₂ + H₂O → NaHCO₃ + NH₄Cl
2 NaHCO₃ → Na₂CO₃ + H₂O + CO₂

Meanwhile, Sodium carbonate can also be prepared by ammonia, carbon dioxide and saturation salt, called as union system alkaline which is improved from Solvay process by Hou Debang. This reaction has three steps as the follwing:

NH₃ + CO₂ + H₂O → NH₄HCO₃
NH₄HCO₃ + NaCl → NaHCO₃ + NH₄Cl
2 NaHCO₃ → Na₂CO₃ + CO₂ + H₂O

Uses: Sodium carbonate is domestically well known for its everyday use as a water softener. It also has the most important use to manufacture glass. Sodium carbonate is also used as a relatively strong base in various settings. For example, sodium carbonate is used as a pH regulator to maintain stable alkaline conditions necessary for the action of the majority of developing agents. In domestic use, Sodium carbonate is used as a water softener during laundry. It is often used as an electrolyte in chemistry. This is because electrolytes are usually salt-based, and sodium carbonate acts as a very good conductor in the process of electrolysis. It is also used as a primary standard for acid-base titrations because it is solid and air-stable, making it easy to weigh accurately. In dyeing with fiber-reactive dyes, sodium carbonate is used to ensure proper chemical bonding of the dye with the fibers, typically before dyeing, mixed with the dye, or after dyeing.

When using Sodium carbonate, you must be cautious about it. The substance is irritant to eyes, respiratory system and skin and toxic to aquatic organisms which may cause long-term adverse effects in the aquatic environment. Whenever you will contact or use it, you must wear suitable protective clothing, gloves and eye/face protection.

Descriptors computed from structure of Sodium carbonate:
(1)Canonical SMILES: C(=O)([O-])[O-].[Na+].[Na+]
(2)InChI: InChI=1S/CH2O3.2Na/c2-1(3)4;;/h(H2,2,3,4);;/q;2*+1/p-2
(3)InChIKey: CDBYLPFSWZWCQE-UHFFFAOYSA-L

Toxicity of Sodium carbonate: