10n naoh what percentage



  Caustic soda is the name for solutions of sodium hydroxide (NaOH) in water. These solutions are alkaline solutions.

The sodium hydroxide dissolves very well in water with strong heat generation. An aqueous solution saturated at room temperature contains 1260 g sodium hydroxide per liter. Caustic soda is one of the most widely used laboratory and industrial chemicals. Concentrated caustic soda has a very corrosive effect on the skin and even very dilute caustic soda can damage the cornea of ​​the eyes to such an extent that it leads to blindness.

One molar sodium hydroxide solution (a solution that contains one mole of NaOH (40 g) in one liter; corresponds to about 3.9% by weight) has a pH value of 14.

The base strength is pKb = −2,43.

Mass content of NaOH (wt.%) 4,0 10,0 20,0 30,0 40,0 50,0
Molarity NaOH
(minor)
1,04 2,77 6,09 9,95 14,30 19,05
Concentration NaOH
(g / l)
41,7 110,9 243,8 398,3 572,0 762,2
Density of the solution
(g / cm3)
1,043 1,109 1,219 1,328 1,430 1,524

Extraction

Sodium hydroxide is mostly obtained from sodium chloride by electrolysis (around 65 percent of world production). This also produces chlorine. The chemical industry's great need for caustic soda has made a significant contribution to the development of chlorine chemistry (example: polyvinyl chloride as a further use of chlorine).

use

  • Cleaning: rinsing of bottles in beverage filling plants (breweries and other beverage processing companies), pipe cleaners, removal of greasy and oily contaminants
  • Production of soaps, digestion of bauxite (for aluminum extraction) and other ores, pulp extraction
  • Processing: stripping of wood, large-scale peeling (e.g. of potatoes), neutralization of acids, regeneration of rubber and ion exchangers, refinement of cotton (mercerization)
  • further use in photography, for the preservation of old documents
  • develop exposed circuit boards for the production of printed circuits that have previously been coated with a special lacquer (photo-positive).
  • Production of pretzels (e.g. pretzels or pretzel sticks)
  • Drain-free (One tablespoon of NaOH together with a cup of warm water down the drain of a clogged sink, for example)
  • Cleavage of DNA double strands into single strands by breaking the hydrogen bonds between complementary nucleotide bases.

storage

Caustic soda should never be stored in vessels with ground glass stoppers. With the carbon dioxide from the air, sodium hydrogen carbonate is formed on the joint.

This salt crust sticks the joint to the sleeve. Instead, a plastic container made of z. B. PE-HD with screw cap or rubber stopper.

disposal

Since caustic soda itself is very often used to bind other chemicals that are very dangerous for the environment, there is no objection to discharging uncontaminated caustic soda sufficiently diluted into the sewer system, provided the wastewater is fed to a sewage treatment plant.

Categories: Chemical Solution | base