Oxalic acid is the first series of dicarboxylic acids, its salts (oxalates) are prevalent in nature, for example, in plants of the oxalate family. The Formula for oxalic acid is (COOH) 2. It is a monobasic acid formed from cyanogen. Oxalic acid is used as a bleaching agent for rust and ink stains, in textile and leather production and a monoglyceryl oxalate in the manufacture of allyl alcohol and formic acid.
For example, sodium oxalate which is an Ionic compound formed from sodium salt of oxalic acid comprised of Na+ and C2O42− ions combined in a 2:1 ratio. When carbon monoxide and solid sodium hydroxide are heated under 8-10 atmospheric pressure, sodium formate is formed. This on further heated rapidly at 360oC gives sodium oxalate.
Is oxalic acid ionic or covalent?
A formula unit of an ionic compound is the smallest whole-number ratio of ions present. Ionic compounds are crystalline solids formed by neatly packed ions of opposite charge. Covalent compounds might be solid, liquid, or gas at room temperature, and they exist as molecules.
Oxalic acid forms with monatomic alcohol-radicles two series of ethers, analogous to the neutral and acid metallic oxalates. Oxalic acid is distilled with absolute alcohol both the type of esters are simultaneously formed called ethyl hydrogen oxalate and ethyl oxalate.
Health Effects of Oxalic Acid
The health risk on exposure to oxalic acid are listed below.
- If humans and animals eat oxalic acid or oxalate, this can cause irritation in the throat, mouth, and other mucous membranes that also discourage insects from eating plants.
- Oxalic acid is a strong acid which, in solid form or in concentrated solutions, can cause burns of the skin, eyes or mucous membrane.
- Certain types of calcifications are composed of calcium oxalate. Kidney stones are a good example. Approximately 75% of kidney stones are of the calcium oxalate variety.
- Swallowing strong oxalic acid results in corrosion of the mouth, esophagus, and stomach.
- Oxalic acid is caustic on the skin. Cracking and fissuring of the skin and development of slow healing ulcers are common responses to repeated skin contact.
Oxalic acid is used by a variety of industries but there is little recent information available on how many workers may be exposed to the chemical. People who work with dentist or the dentists themselves may also be exposed to oxalic acid. Some heavy duty household cleaners and polishes use oxalic acid. Avoid direct contact with strong oxalic acid solutions or powder whenever possible.