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Sodium Nitrite

Sodium nitrite represented by the chemical formula NaNO2 is a nitrous acid sodium salt [1] that is soluble in water and aqueous acid [4]. It is non-combustible itself but assists the burning of combustible material [1]. It is an ionic compound and a strong reducing agent [3]. In acidic solution, though, it mainly executes oxidation reactions [4].

Sodium Nitrite

Sodium Nitrite Identification

CAS Number 7632-00-0 [1]
PubChem CID 23668193 [1]
ChemSpider ID 22689 [2]
EC Number 231-555-9 [1]

Composition and Synthesis

Sodium nitrite can be prepared by heating sodium nitrate and lead [7].

NaNO3 + Pb = NaNO2 + PbO

Sodium Nitrite Formula

Properties and Characteristics of Sodium Nitrite

General Properties

Molar mass/molecular weight 68.995 g/mol [1]

Physical Properties

Color/appearance Yellowish white crystals [1]
Melting point/freezing point 271°C, 519.8°F [5]
Boiling point 320°C, 608°F (decomposes) [1]
Density 2.17 g cm-3 [5]
State of matter at room temperature (normal phase) Solid [1]
Vapor pressure 0.2 [6]

Chemical Properties

Solubility in water 820 g/l (at 20oC) [4]
pH 9 (basic) [4]

Atomic Properties

Crystal structure Orthorhombic [1]

Sodium Nitrite Structure

Prominent Reactions

On heating ammonium chloride with sodium nitrite, initially, ammonium nitrite and sodium chloride are formed. Then ammonium nitrite decomposes into nitrogen and water [9].

NH4Cl + NaNO2 = NH4NO2 + NaCl

NH4NO2 = N2 + 2H2O

It reacts with concentrated hydrochloric acid under boiling condition to produce sodium nitrate, sodium chloride, nitric oxide and water [11].

3NaNO2 + 2HCl = NaNO3 + 2NaCl + 2NO + H2O

Sodium nitrite reacts with sulfuric acid to form sodium sulfate, nitrogen dioxide, nitric oxide and water [12].

2NaNO2 + H2SO4 = Na2SO4 + NO2 + NO + H2O

Sodium Nitrite Uses

  1. In meat curing, preservation and coloring [1].
  2. As a reagent in techniques involving analytical chemistry [1].
  3. As a corrosion inhibitor, food additive, hog poison and an antidote to cyanide poisoning (used in combination with sodium thiosulfate) [1, 4].
  4. For the production of various dyes and fertilizers [1, 4].
  5. For bleaching fibers and printing textile fabrics [3].
  6. As a laxative, bronchodilator and vasodilator in the medical field [3].

Is It Harmful

The compound is highly toxic and if ingested it may cause cyanosis, convulsions and even death. It causes digestive tract, skin and eye irritation on contact. If inhaled, it may be fatal. It can cause cancer and an explosion or fire hazard [6]. Repeated exposure may have an acutely poisonous effect on health. Having it during pregnancy may pose a health risk by increasing the probability of brain tumors in the baby [10].

Sodium Nitrite (NaNO2) Price

The compound costs around $400 – $500 for every metric ton. The price may vary slightly across suppliers [8].

References:

  1. Sodium Nitrite – Pubchem.ncbi.nlm.nih.gov
  2. Sodium Nitrite – Chemspider.com
  3. Sodium Nitrite – Fearschemistry.wikidot.com
  4. Sodium Nitrite – Chemicalbook.com
  5. Sodium Nitrite – Americanelements.com
  6. Sodium Nitrite (7632-00-0) – Chemicalbook.com
  7. Preparation of sodium nitrite – Prepchem.com
  8. Sodium nitrite price – Alibaba.com
  9. What is the gas produced by heating ammonium chloride with sodium nitrite? – Quora.com
  10. Maternal consumption of cured meats and vitamins in relation to pediatric brain tumors. – Ncbi.nlm.nih.gov
  11. Sodium nitrite react with hydrogen chloride – Chemiday.com
  12. Sodium nitrite react with sulfuric acid – Chemiday.com

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