What is the Difference Between Boric Acid and Borax?

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Boric acid and borax are both borates, which are compounds derived from the element boron. They share some similarities, but they also have distinct differences. Here are the main differences between boric acid and borax:

  1. Origin: Borax is a naturally occurring mineral made up of sodium, oxygen, and boron, while boric acid is a refined and processed compound created from the mixture of borax with other naturally occurring minerals.
  2. Structure: Borax contains sodium, which boric acid does not have. Borax has a molecular weight of 381.43, while boric acid has a molecular weight of 61.83.
  3. Physical properties: Borax is a white crystalline solid with a pH value of 5.1 and a melting point of 170.9°C. Boric acid is also a white crystalline solid but has a pH value of 9.5 and a melting point of 743°C.
  4. Solubility: Boric acid is more soluble in water than borax. Boric acid is soluble at 31.7 g/L, while borax is soluble at 2.52 g/100 mL at 0°C, 4.72 g/100 mL at 20°C, and 27.53 g/100 mL at 100°C.
  5. Applications: Both boric acid and borax have several uses, some of which overlap. They are both used in cleaning products and as insecticides. However, boric acid is more commonly used industrially to produce fiberglass, LCD screens, ceramics, and as a food preservative in some countries. Borax, on the other hand, is more commonly used as a household detergent, cleaning item, antifungal agent, preservative, fire retardant, and ingredient in making various kinds of glass.
  6. Effectiveness: Boric acid is generally considered more effective than borax for insect control. Its smaller grains make it harder for pests to detect and easier to ingest, making it more effective at killing pests than borax.

Comparative Table: Boric Acid vs Borax

Here is a table comparing the differences between boric acid and borax:

Property Boric Acid Borax
Chemical Formula H3BO3 Na2B4O7 • 10H2O
Molecular Weight 61.83 381.43
Composition Boron, Hydrogen, and Oxygen Sodium, Oxygen, and Boron
Natural Form Crystals Mineral (Sodium Tetraborate)
Water Molecules 0 10
Boron Concentration 17.48% 11.34%
Common Uses Detergents, cosmetics, fire retardant, anti-fungal compound, buffer solution in biochemistry Laundry detergents, cleaners, soldering flux
Melting Point Relatively higher, more active at higher temperatures Lower, more active at lower temperatures

Boric acid is a compound containing boron, hydrogen, and oxygen, while borax is a natural mineral made up of sodium, oxygen, and boron. Boric acid is created from a mixture of borax and other naturally occurring minerals. Both boric acid and borax can be used as all-purpose cleaners, effective stain-removers, disinfectants, deodorizers, and mold-killers.