Oxalic acid is white crystals, much like sugar. Before washing, dissolve one part of oxalic acid in 20 parts of water to make an oxalic acid solution. Then, drop it on the rust spots of the clothes, after scrubbing and rinsing, the rust is gone. Oxalic acid can remove rust because of its strong reducing ability. The iron in the rust spots is trivalent iron, which is not soluble in water. When it touches oxalic acid, it is reduced to divalent iron and can be dissolved in water.
Oxalic acid can also deal with iron in blue ink. If you accidentally get blue ink on your clothes, you have to rinse them with clean water as soon as possible. If it takes a long time, it will be difficult to wash off. Because there is a compound called ferrous tannate in blue ink, it will be oxidized to colored iron tannate when it encounters oxygen in the air. Iron tannate does not dissolve in water, so the ink stain cannot be washed off with water. If oxalic acid is used to reduce iron tannate and dissolve it in water, the ink stains on the clothes can be washed away.
Although oxalic acid can help wash away rust and blue ink stains, it can also corrode clothes and wash away the color of clothes. Therefore, before washing the stain with oxalic acid solution, it is best to try it in unobtrusive places such as the corners of the clothes to see if the color will fade. In addition, after washing the ink stains with oxalic acid, wash it with water several times to prevent excess oxalic acid from remaining on the clothes.
1. Used as a bleaching agent: Oxalic acid is mainly used as a reducing agent and a bleaching agent, used in the production of antibiotics, borneol and other drugs, as well as solvents for extracting rare metals, dye reducing agents, tanning agents, etc. Oxalic acid can also be used in the production of cobalt-molybdenum-aluminum catalysts, the cleaning of metals and marbles, and the bleaching of textiles.
2. As a reducing agent: In the organic synthesis industry, it is mainly used to produce chemical products such as hydroquinone, pentaerythritol, cobalt oxalate, nickel oxalate, gallic acid and so on. In addition, oxalic acid can also be used to synthesize various products such as oxalate, oxalate and oxalamide, and diethyl oxalate, sodium oxalate, and calcium oxalate have the largest yields.
3. As a mordant: antimony oxalate can be used as a mordant, and ferric ammonium oxalate is a medicament for printing blueprints.