- What it is. This sodium hydroxide is a 35% (w/w) aqueous solution supplied in a 1-gallon size. It is a clear, colorless, strongly alkaline liquid for laboratory and pilot-scale cleaning, digestion, pH control, and reagent preparation.
- Concentration. Every 100 g of solution contains 35 g of sodium hydroxide. That places it between common 30% and 50% caustic strengths, delivering high alkalinity while staying liquid at lower temperatures than 50% solutions.
- Chemical identity. Sodium hydroxide (caustic soda, CAS 1310-73-2, NaOH, 40.00 g/mol) is a strong base that dissociates completely in water. It neutralizes acids, saponifies fats and oils, and dissolves aluminum, zinc, and many organic residues.
- Why buy a liquid concentrate. Dissolving solid sodium hydroxide releases a large amount of heat and creates caustic dust and spatter. A prepared solution removes that hazard, is easier to meter and pump, and gives consistent strength for dilution and dosing.
- Laboratory uses. Labs use concentrated sodium hydroxide to prepare dilute bases, raise pH quickly in large volumes, digest organic samples, neutralize acid spills and waste, and run saponification and alkaline hydrolysis reactions.
- Cleaning glassware and equipment. Strong caustic solutions remove grease, proteins, and stubborn organic residues from glassware and stainless steel equipment, though prolonged contact with hot caustic slowly etches glass.
- Gallon size. The 1-gallon size suits laboratories and pilot plants that need concentrated caustic regularly but not at drum scale.
- Carbon dioxide uptake. Like all hydroxide solutions, sodium hydroxide absorbs carbon dioxide from the air, forming sodium carbonate and slowly lowering effective alkalinity. Keep containers sealed between uses.
- Handling at a glance. Concentrated sodium hydroxide causes severe burns that may not be immediately painful, and it is especially damaging to the eyes. Wear chemical splash goggles, a face shield, and alkali-resistant gloves, and keep an eyewash station and safety shower nearby.
- Where it is used. Labs and pilot plants use 35% sodium hydroxide to prepare dilute bases, adjust pH, digest samples, clean equipment, neutralize acidic waste, and run alkaline reactions in chemical synthesis.
Technical Specifications
| Chemical Name | Sodium hydroxide, aqueous solution |
| CAS Numbers | 1310-73-2 (sodium hydroxide); 7732-18-5 (water) |
| EC Number (NaOH) | 215-185-5 |
| Synonyms | Caustic soda solution, lye solution, NaOH solution |
| Formula (active) | NaOH |
| Molecular Weight (active) | 40.00 g/mol |
| Concentration | 35% (w/w) |
| Appearance | Clear, colorless liquid |
| Water Solubility | Miscible |
| Hazard Statements (typical NaOH solutions) | H290 (corrosive to metals), H314 (severe burns) |
| DOT (typical) | UN1824, Sodium hydroxide solution, Class 8 ( SDS) |
| Exposure Limit | NIOSH REL 2 mg/m³ ceiling |
| Package Size | 1 gallon |
Applications / Common Uses
- Dilute base preparation: Prepares working-strength NaOH solutions.
- pH adjustment: Raises pH in large volumes.
- Sample digestion: Digests organic matter in alkaline methods.
- Equipment cleaning: Removes grease and organic residues.
- Waste neutralization: Neutralizes acidic waste streams.
Storage, Handling & Shipping
Caution: Concentrated sodium hydroxide causes severe skin burns and eye damage and is corrosive to aluminum and zinc. Wear chemical splash goggles, a face shield, and alkali-resistant gloves, and always add base slowly to water when diluting.
Store tightly closed in a corrosives area for bases, separated from acids, reactive metals such as aluminum and zinc, and organic halogen compounds. Use secondary containment and keep containers sealed to limit carbon dioxide uptake.
- Incompatible materials: Acids, aluminum, zinc, tin, and other reactive metals, and organic halogen compounds.
- Exposure limit (NaOH): NIOSH REL 2 mg/m³ ceiling.
- Spill response: Contain with inert absorbent, neutralize cautiously with a weak acid, and rinse with water.
- First aid: Skin or eyes: flush with water for at least 15 minutes and seek immediate medical attention.
Related Categories & Services
- Shop Bases for related products in this category.
- Explore Inorganic Chemicals and ACS Grade Laboratory Chemicals.
- Vendor Managed Inventory (VMI) Program: Lab Pro can stock, track, and replenish this item on site so it never runs out. Contact info@labproinc.com or 888-452-2776 to set up a VMI assessment.
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FAQs
What is 35% sodium hydroxide used for?
It is used to prepare dilute bases, adjust pH in large volumes, digest organic samples, clean glassware and stainless steel equipment, neutralize acidic waste, and run alkaline reactions. Its high concentration means small volumes deliver substantial alkalinity, which keeps dilution volumes manageable. It also serves as a pilot-scale cleaning concentrate.
How do I dilute 35% sodium hydroxide?
Wear goggles, a face shield, and alkali-resistant gloves, then add the solution slowly to cold water while stirring. Never add water to the concentrate. Dilution releases heat, so cool the solution before bringing it to final volume and standardize it if needed. Label the result.
Can sodium hydroxide damage glassware?
Yes, slowly. Hot or concentrated sodium hydroxide dissolves silica from glass over time, etching surfaces and weakening volumetric glassware. Use plastic containers for storing concentrated caustic, limit contact time when cleaning glassware, and rinse thoroughly afterward. Never store caustic in volumetric flasks, since etching changes their calibrated volume over time.
Why does concentrated caustic absorb carbon dioxide?
Sodium hydroxide reacts with carbon dioxide in air to form sodium carbonate. Over time, that lowers the effective hydroxide content and can form white crusts around openings. Keep the container tightly closed between uses to protect the solution's strength. Wipe crusts away with gloves on.
What PPE is required for 35% sodium hydroxide?
Wear chemical splash goggles, a face shield, alkali-resistant gloves (e.g., neoprene or butyl), and a lab coat or apron. Work where an eyewash station and safety shower are available, since caustic burns progress quickly and require immediate, prolonged rinsing. Remove contaminated clothing promptly. Never work alone.
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