Potassium Hydroxide (KOH): Properties, Safety, Uses, and Buying Guide
Release time: 2025-10-27
Potassium hydroxide, also known as caustic potash or lye, is a strong inorganic base widely used in industry. Its chemical formula is KOH and its CAS number is 1310-58-3. KOH is a white, odorless solid flakes that readily absorbs moisture (deliquescent). It is highly soluble in water, producing a strongly alkaline solution. Below are its key properties, applications, and safety information. High-purity KOH(45-52%/90%/95%) is available from BLi-T (Hefei) Chemical Co., Ltd, with complete documentation (COA, MSDS) and global logistics support (contact info@blitchem.com for samples or orders).
Properties and Chemical Formula of Potassium Hydroxide
Potassium hydroxide typically appears as a white solid (often in flake or pellet form). It is hygroscopic (deliquescent) and odorless. Its chemical formula is KOH, and CAS number is 1310-58-3. KOH has a molar mass of 56.11 g/mol. Key physical properties include:
- Appearance: White, deliquescent flakes. (Keep containers tightly closed.)
- Melting Point: ≈ 380 °C;
- Density: ~2.044 g/cm³ (solid, 20 °C).
- Solubility: Highly soluble in water – about 121 g per 100 mL at 25 °C (solubility increases with temperature). It is also soluble in alcohols and glycerol; insoluble in ether or liquid ammonia.
- Basicity (pKa): KOH is a very strong base (conjugate acid pK_a ≈ 14.7). In water it dissociates completely into K⁺ and OH⁻ ions.
Each of the above properties is well-documented in chemical references. High-purity grades of KOH (90–95% solid flakes or pellets) are supplied by BLi-T for demanding applications.
Electrolyte Behavior and pH
KOH is a strong electrolyte in aqueous solution. It dissociates fully into potassium (K⁺) and hydroxide (OH⁻) ions, making the solution highly conductive. In fact, aqueous KOH is commonly used as the electrolyte in alkaline batteries (nickel–cadmium, nickel–metal hydride, and zinc–manganese cells). These batteries use KOH instead of NaOH because KOH solutions conduct electricity even better.
As a strong base, KOH raises the pH of water dramatically. Even dilute KOH solutions are very alkaline: for example, a 0.05 M KOH solution has a pH around 12.7. More concentrated solutions approach a pH of 14. In general, potassium hydroxide solutions have extremely high pH (typically above 12). This is why KOH is used to neutralize acids and control pH in many industrial processes.
Safety and Handling of Potassium Hydroxide
Potassium hydroxide is highly caustic and corrosive. It can cause severe chemical burns on skin and eyes, and its dust or mist can damage the respiratory tract. Key safety information includes:
- Hazards: Signal word “Danger”. KOH is corrosive to metals and tissue. It causes severe skin burns and eye damage. Inhalation of dust or mist can lead to pulmonary edema. Even in dilute form it is irritating; concentrated solutions are extremely corrosive.
- Personal Protective Equipment (PPE): Always wear chemical-resistant gloves, safety goggles or face shield, and protective clothing when handling KOH. Work in a well-ventilated area to avoid breathing fumes or aerosols. Do not eat, drink or smoke while handling this chemical.
- First Aid: In case of skin or eye contact, immediately flush with plenty of water for at least 15 minutes. Remove contaminated clothing while flushing skin. Seek medical attention if irritation or burns occur. If inhaled, move to fresh air. If ingested, rinse mouth and do not induce vomiting; get emergency help.
- Storage: Store KOH in a tightly closed container in a cool, dry, well-ventilated area. Use corrosion-resistant storage containers (e.g. plastic or glass) and keep away from acids and moisture. Because it absorbs water, containers should be kept closed and dry. For concentrated or large quantities, keep stored in a locked area and clearly labeled.
- Spill Response: Avoid contact; wear full PPE. Neutralize any spills with a dilute acid (e.g. vinegar) before clean-up. Contain and sweep up the solid; dispose of waste in accordance with local regulations.
Hazard classification (per GHS) includes Skin Corrosion/Irritation Category 1 (H314: causes severe burns). As noted above, consult the Safety Data Sheet (MSDS) before use. BLi-T Chem provides full documentation (TDS,MSDS, COA) with every shipment to ensure safe handling.
Applications of Potassium Hydroxide
Potassium hydroxide has a wide range of industrial uses thanks to its strong alkalinity:
- Soaps & Detergents: KOH saponifies fats to make potassium soaps, which are softer and more soluble than sodium soaps. This is key in producing liquid soaps and shaving creams. KOH soaps require less water to liquefy, providing more efficient cleaning.
- Biodiesel Production: KOH acts as a catalyst for converting vegetable oils or animal fats into biodiesel. In this process, KOH is first dissolved in methanol; the mixture is then reacted with oil to produce methyl esters (biodiesel) and glycerin. (After reaction, residual KOH/glycerin can even be used to make soap or fertilizer.) Potassium hydroxide serves as a catalyst in biodiesel production, converting plant oils or waste fats into renewable diesel fuel. This renewable fuel (biodiesel) burns cleaner than fossil diesel while using existing diesel engines.
- Fertilizers & Chemicals: KOH is used to make potassium salts (e.g. potassium carbonate, phosphate, silicates) by neutralizing acids or oxide precursors. For example, highly soluble potassium phosphate (from KOH + phosphoric acid) is used in fertilizers. The high solubility of KOH-derived potassium salts makes them valuable in agricultural chemicals.
- Alkaline Batteries: As noted above, KOH is the electrolyte in many alkaline batteries. It ensures high conductivity and stable pH in NiCd, NiMH, and other rechargeable cells.
- Food Industry: Food-grade KOH (E525) is approved as a food additive for pH adjustment, peeling fruits/vegetables, and food thickening. When used properly, it meets regulatory standards (e.g. REACH, FDA).
- Pharmaceutical & Cosmetics: KOH is used in pharmaceutical synthesis (e.g. to make certain steroids and reagents) and in cosmetics for pH adjustment. Its presence in cleansers, exfoliants or hair-removal products takes advantage of its caustic nature (always formulated safely and with controlled concentration).
- Laboratory & Manufacturing: KOH is a common reagent in organic synthesis (strong base for deprotonation, nucleophilic attacks) and in semiconductor fabrication (silicon etching). It is also used in cleaning agents and drain cleaners for its ability to dissolve organic material.
These applications demonstrate KOH’s versatility as a strong base in soaps, biodiesel catalysts, chemical manufacture, agriculture, electronics, and more. BLi-T supplies KOH suitable for all these uses, from industrial-grade to electronic/pharmaceutical grade, meeting purity and documentation requirements for each industry.
High-Purity KOH from BLi-T (Hefei) Chemical Co., Ltd.
BLi-T (Hefei) Chemical Co., Ltd. is a professional supplier of potassium hydroxide. We offer high-purity KOH in both solid (flakes or pellets, 90–95% purity) and liquid (48–50%) forms, with custom packaging (25 kg bags up to 1000 kg totes). Our KOH meets stringent international quality standards (available in electronic-, pharmaceutical-, food-, and industrial grades).
| Type | Food grade | 90% | 95% | 48% |
| Appearance | White flakes | White flakes | White flakes | Colorless transparent liquid |
| KOH Assay % | 85.0-100 | ≥90.0 | ≥95.0 | ≥48 |
| Carbonate (as K₂CO₃) % | ≤2.0 | ≤0.5 | ≤0.5 | – |
| Hg (mg/kg) % | ≤0.1 | – | – | – |
| As (mg/kg) % | ≤3 | – | – | – |
| Pb (mg/kg) % | ≤5 | – | – | ≤0.001 |
| Heavy metal (as Pb) % | 10 | ≤0.002 | ≤0.002 | – |
| Chlorides (asCl) % | – | ≤0.005 | ≤0.005 | ≤0.002 |
| Sulfates (as SO₄ ) % | – | ≤0.005 | ≤0.005 | – |
| Phosphate (as PO₄) % | – | ≤0.005 | ≤0.005 | – |
| Nitrate (as N) % | – | ≤0.0005 | ≤0.0005 | – |
| Silicate (as SiO₃) % | – | ≤0.01 | ≤0.01 | – |
| Fe % | – | ≤0.0005 | ≤0.0005 | ≤0.0002 |
| Na % | – | ≤1.0 | ≤0.5 | ≤0.4 |
| Al % | – | ≤0.002 | ≤0.002 | ≤0.0005 |
| Ca % | – | ≤0.005 | ≤0.005 | – |
| Ni % | – | ≤0.001 | ≤0.0005 | – |
Notice:“-” Indicates that there is no test item for potassium hydroxide in this table,If you need more information, please contact BLIT CHEM, they have a full set of product information.
Every batch is accompanied by a Certificate of Analysis (COA) and Material Safety Data Sheet (MSDS) detailing purity, heavy metals, moisture content, and handling instructions. We maintain full traceability and ensure products are REACH compliant (food-grade KOH approved for export to Europe, E525). Global logistics support means we can ship KOH to customers worldwide; our products have been exported to 60+ countries. Whether you need KOH for high-tech electronics or bulk industrial production, BLi-T provides reliable supply and technical support.
Packaging & Delivery: BLi-T Chem offers KOH in convenient packaging and small quantity packaging (IBC, ISO tanks for liquids; drum, bag, pallet for solids). We use corrosion-resistant containers and certified pallets to ensure safe transport. Rapid delivery and custom clearing documentation are available to meet your schedule.
For bulk purchases or sample requests, please contact us at info@blitchem.com. We will provide a competitive quote and arrange testing samples with minimal lead time.
FAQ
Q: What are the properties of potassium hydroxide?
A: Potassium hydroxide (KOH) is a white, deliquescent solid with chemical formula KOH. It has a molar mass of 56.11 g/mol and is a very strong base (pK_a ≈ 14.7). Key physical properties include a melting point around 410 °C and boiling point around 1327 °C. KOH dissolves readily in water (about 121 g/100 mL at 25 °C), forming a highly alkaline solution (pH often above 13). It is also soluble in lower alcohols. It is odorless and must be kept dry, as it absorbs moisture from air.
- Q: What is the chemical formula and CAS number of potassium hydroxide?
A: The chemical formula of potassium hydroxide is KOH. The CAS registry number is 1310-58-3. These identifiers apply to pure potassium hydroxide in any form. BLi-T labels its product with this information to ensure traceability. - Q: Is KOH an electrolyte?
A: Yes. KOH is a strong electrolyte because it dissociates completely in water into K⁺ and OH⁻ ions. Its aqueous solutions conduct electricity well. In fact, KOH solution is the standard electrolyte for many alkaline batteries (NiCd, NiMH, etc.). This high conductivity is why KOH is preferred over NaOH in such batteries. - Q: What is the pH of a potassium hydroxide solution?
A: KOH solutions are very alkaline. The exact pH depends on concentration, but even dilute KOH yields high pH. For example, a 0.05 M KOH solution has a pH of about 12.7. At higher concentrations, pH approaches 14. In general, you can expect a strong KOH solution to have pH in the 13–14 range. - Q: What safety precautions are required for potassium hydroxide?
A: KOH is highly caustic and must be handled with care. Always wear protective gloves, goggles, and clothing to avoid skin or eye contact. Use KOH only in well-ventilated areas to prevent inhalation of dust or mist. In case of contact, immediately rinse affected area with copious water for ≥15 minutes. Store KOH in a tightly sealed container in a cool, dry place. Never mix KOH with acids or water in an uncontrolled manner (add chemical to water slowly if diluting). Refer to the MSDS for detailed hazard and first-aid instructions. Remember: KOH can cause severe burns and must be treated with respect. - Q: How can I buy potassium hydroxide (KOH)?
A: For purchasing high-purity KOH, contact BLi-T (Hefei) Chemical Co., Ltd. We supply bulk solid or liquid KOH with complete documentation (COA, MSDS) for quality assurance. Email info@blitchem.com to request a quote or sample. Specify the grade and quantity you need. We offer worldwide shipping and can tailor packaging to your requirements. - Q: What is the CAS number of KOH and why is it important?
A: The CAS number for potassium hydroxide is 1310-58-3. This unique identifier ensures you and suppliers are talking about the exact same substance. You can use the CAS number to check regulatory information, sourcing, and compatibility. All BLi-T KOH products are labeled with this CAS number. - Q: Is KOH safe for consumer products?
A: In concentrated form, KOH is not safe to touch or ingest because it is corrosive. However, in regulated, low concentrations it is used safely. For instance, food-grade KOH (E525) is approved by the FDA for certain food processing uses. Similarly, KOH can be found in skincare or hair-care products in well-formulated recipes (e.g. as a pH adjuster or keratolytic). In all cases, safety guidelines must be followed. BLi-T supplies KOH of the purity required for each application and provides safety documentation to ensure it is used correctly.
Note: Always refer to the current Safety Data Sheet (MSDS) for detailed handling instructions and emergency measures. By adhering to these guidelines and using high-purity, documented KOH from BLi-T Chem, you can safely incorporate potassium hydroxide into your processes.
