Sodium Chromate

Syllabus: General Studies Paper 3

A section of environmentalists have flagged irregularities in the draft Environmental Impact Assessment report for a proposed chemical plant in Telangana’s Nalgonda district.

• The project uses outdated technology to produce sodium dichromate from chromite ore, while disguising itself as a sodium saccharin unit.
• Sodium dichromate is a hazardous chemical. It is corrosive to the eyes, skin and respiratory tract. Exposure to the substance may cause affect kidney and liver.
• The company abandoned 100,000 tonnes of chromite ore processing residue, which continuously leached hexavalent chromium through a stream joining the Krishna.
• The substance is very toxic to aquatic organisms. It may cause long-term effects on the marine environment. It is strongly advised not to let the chemicals enter the environment.

Sodium Chromate

• Sodium chromate is the inorganic compound with the formula Na2CrO4.
• It exists as a yellow hygroscopic solid, which can form tetra-, hexa-, and decahydrates.
• It is an intermediate in the extraction of chromium from its ores.
• Sodium chromate is
• It is obtained on a vast scale by roasting chromium ores in air in the presence of sodium carbonate
• The compound is also corrosive and exposure may produce severe eye damage or blindness.
• Human exposure further encompasses impaired fertility, heritable genetic damage and harm to unborn children.

Sodium Dichromate

• Sodium chromate converts to sodium dichromate when treated with acids.
• Sodium dichromate is a hazardous chemical.
• It is corrosive to the eyes, skin and respiratory tract.
• Exposure to the substance may cause affect kidney and liver.
• Even a brief exposure to the substance can damage tissues.
• Repeated or prolonged inhalation may cause nasal ulceration. This may result in perforation of the nasal septum.
• The substance is very toxic to aquatic organisms.
• It may cause long-term effects on the marine environment.

Uses of Sodium Chromate

• Production of chromium from its ores.
• Used as a corrosion inhibitor in the petroleum industry.
• A dyeing auxiliary in the textile industry.
• A diagnostic pharmaceutical in determining red blood cell volume.
• In organic chemistry, sodium chromate is used as an oxidant, converting primary alcohols to carboxylic acids and secondary alcohols to ketones.
• Sodium chromate is a strong oxidizer.