Sodium bisulfate

 

Sodium bisulfate

Chemical formula	NaHSO4
OTP appearance	white powder
Molar Mass(g/mol)	120.6
Density(g/cc)	1.8
Melting Point(°C)	315
Solubility in water(g/L)	285
NFPA 704	0 2 1
Thermal decomposition of sodium bisulfate monohydrate
58.5	monohydrate 58.5°C anhydrous
315	anhydrous 315°C pyrosulfate
460	pyrosulfate 460°C sulfate + sulfur trioxide

Uses

Other

• Nitric acid, hydrochloric acid and glacial acetic acid can all be produced by dry distillation of their salts with sodium bisulfate.
• Feedstock for production of sulfur trioxide via thermal decomposition
• Sodium bisulfate is used in the production of ammonium nitrate and acetic acid
• Used to lower the pH of tanning solutions without adding an acid

Natural occurrence

• Does not occur naturally.

Production

Synthesis

From dithionite

An aqueous solution of sodium dithionite, in the presence of oxygen, creates both sodium bisulfite and sodium bisulfate:

Na₂S₂O₄(aq) + O₂(aq) + H₂O → NaHSO₄ + NaHSO₃

From bisulfite

Oxidize bisulfite to bisulfate

• Combine sodium bisulfite with a hypochlorite, such as sodium hypochlorite, producing sodium bisulfate

  NaHSO₃ + NaOCl → NaHSO₄ + NaCl

• Combine sodium bisulfite with copper (II) chloride in water, producing sodium bisulfate. The hydrochloric acid can be used to regenerate the CuCl to CuCl₂.

  2 CuCl₂ + Na₂SO₃ + H₂O → 2 CuCl + Na₂SO₄ + 2 HCl

From sulfuric acid

• Neutralize sulfuric acid with sodium sulfate in a 1:1 molar ratio

  Na₂SO₄ + H₂SO₄ → 2 NaHSO₄

• Neutralize sulfuric acid and sodium hydroxide in a 1:1 molar ratio

  NaOH + H₂SO₄ → NaHSO₄ + H₂O

Purification

• Recrystallize from water