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EDTA Titrant 0.05 M (0.1 N), 1 Gallon

$79.54
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SKU: ZE0552-128
California prop 65
Description
  • What it is. This EDTA titrant contains 0.05 moles of disodium EDTA dihydrate per liter, is labeled 0.1 N, and comes in a 1-gallon size. It is a clear, colorless complexometric titrant for calcium, magnesium, and other metals in water and process samples.
  • Why 0.05 M is labeled 0.1 N. EDTA binds divalent metal ions such as calcium and magnesium one-to-one, and each mole corresponds to two equivalents of charge. Expressed as normality, 0.05 M EDTA is therefore 0.1 N. Molarity is the more direct basis for calculations.
  • What each milliliter delivers. One milliliter contains 0.05 millimole of EDTA, which complexes 2.004 mg of calcium, 1.215 mg of magnesium, or the equivalent of 5.005 mg of calcium carbonate (calculated). These factors convert titration volume directly into sample concentration.
  • A versatile working strength. At 0.05 M, the titrant suits moderately hard water, process water, and metal assays where 0.01 M would need large volumes and 0.1 M would give too few milliliters for good precision.
  • Calculating hardness. Multiply the milliliters of titrant used by 5.005 to get milligrams of calcium carbonate equivalent, then divide by the sample volume in liters to report mg/L as CaCO3 (calculated). Subtract a reagent blank first and use the standardized molarity when it differs from 0.05 M.
  • Running a hardness titration. Buffer the sample near pH 10 with an ammonia buffer, add Eriochrome Black T, and titrate from wine red to clear blue. Lab Pro offers Eriochrome Black T Indicator, Ammonium Chloride, ACS Grade, and Ammonium Hydroxide 28 to 30% Solution, ACS Grade for that buffer system.
  • How EDTA works. EDTA is a hexadentate chelating agent that wraps around a metal ion through two nitrogen atoms and four carboxylate groups, forming a stable one-to-one complex. That predictable stoichiometry is what makes EDTA titrations accurate.
  • Standardization and care. For critical work, standardize against calcium carbonate or zinc, keep the container tightly closed, and use deionized water and metal-free labware. The 1-gallon size provides one consistent lot for routine testing over an extended period.
  • Related EDTA products. For higher metal levels, see EDTA Titrant 0.2 N / 0.1 M, 1 gallon or EDTA Disodium Solution, 0.1 M (0.2 N). To prepare custom strengths, use EDTA Disodium Salt Dihydrate, ACS Grade.

Technical Specifications

Chemical Name Ethylenediaminetetraacetic acid disodium salt dihydrate, aqueous solution
Synonyms EDTA titrant, disodium EDTA solution
CAS Numbers 6381-92-6 (disodium EDTA dihydrate); 7732-18-5 (water)
EC Number (active) 205-358-3
Formula (active) C10H14N2Na2O8·2H2O
Molecular Weight (active) 372.24 g/mol
Concentration 0.05 M (0.1 N)
EDTA Content About 18.6 g/L dihydrate (calculated)
EDTA per mL 0.050 mmol
Titration Equivalence 1.00 mL = 2.004 mg Ca, 1.215 mg Mg, or 5.005 mg CaCO3 (calculated)
Binding Ratio 1:1 EDTA to metal ion
Appearance Clear, colorless liquid
Physical State Liquid, aqueous solution
Storage Room temperature, tightly closed
Package Size 1 gallon

Applications / Common Uses

  • Water hardness: Determines total hardness with Eriochrome Black T.
  • Calcium and magnesium: Titrates Ca and Mg in water and process samples.
  • Metal assays: Quantifies zinc, nickel, and other divalent metals.
  • Boiler and cooling water: Monitors hardness in industrial water systems.
  • Teaching labs: Demonstrates complexometric titration.

Storage, Handling & Shipping

Store the solution tightly closed at room temperature to prevent evaporation, which would raise its concentration. Keep it away from strong oxidizers and metal-containing materials, and use clean, metal-free labware so trace metals do not consume EDTA before titration.

  • Incompatible materials: Strong oxidizers, strong acids, and metal salts.
  • Personal protection: Safety glasses and nitrile gloves.
  • Spill response: Absorb with inert material and rinse the area with water.
  • First aid: Eyes: rinse with water for several minutes. Ingestion: rinse mouth and seek medical advice.

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FAQs

Why is 0.05 M EDTA labeled 0.1 N?

EDTA reacts with divalent metal ions in a 1:1 mole ratio, but each mole has two equivalents of charge. In normality terms, a 0.05 M solution is 0.1 N. Most modern methods express EDTA strength in molarity, since one mole of EDTA binds one mole of metal.

How do I calculate hardness from my titration?

Multiply the titrant volume (mL) by 5.005 to get mg of calcium carbonate equivalent in the sample, then divide by the sample volume (L) to get mg/L as CaCO3. Subtract any blank volume first, and use the standardized molarity if it differs from 0.05 M.

When is 0.05 M the right strength?

Choose 0.05 M for moderately hard water, process water, and metal assays, where titration volumes stay in a precise, practical range. Dilute samples are better served by a weaker titrant, and concentrated samples by 0.1 M, so match the strength to your expected concentration. Your method may also specify a strength.

What indicator works with EDTA titrations?

For calcium plus magnesium, Eriochrome Black T in an ammonia buffer near pH 10 gives a wine red to clear blue endpoint. For calcium alone, methods raise the pH to about 12 so magnesium precipitates, then use a calcium-selective indicator such as murexide. Keep indicator additions consistent between samples.

How should EDTA titrant be stored?

Keep it tightly closed at room temperature to prevent evaporation, which would raise the concentration. Use clean, metal-free labware so trace metals do not consume titrant, and restandardize periodically against calcium carbonate or zinc when your results depend on exact molarity. Label the date the container was opened.