Eriochrome black T , 25gm

Eriochrome black T (EBT) is a complexometric indicator that is used in complexometric titrations, e.g., in the water hardness determination process. It is an azo dye. Eriochrome is a trademark of Huntsman Petrochemical, LLC. In its deprotonated form, Eriochrome Black T is blue. It turns red when it forms a complex with calcium, magnesium, or other metal ions. EBT is blue in a buffered solution at pH 10. It turns red when Ca2+ ions are added.

EBT is a sensitive indicator for calcium and magnesium, but it is not specific. Other compounds containing a metal ion with a hard water ion can also give a positive EBT test. Therefore, the murexide test or the eriochrome cyanine R test are often used along with the EBT test to confirm the presence of calcium and magnesium.

EBT is a relatively simple test to perform, but it is important to follow the safety precautions carefully. EBT is a corrosive and can cause skin burns and eye irritation. It is also toxic if ingested.

Here are the steps on how to perform the EBT test:

1. Prepare a solution of calcium or magnesium ions in water or dilute acid.
2. Add a few drops of EBT to the solution.
3. If calcium or magnesium ions are present, the solution will turn red.

Here are some safety precautions to take when using EBT:

• Wear gloves, eye protection, and a lab coat when working with EBT.
• Avoid contact with skin and eyes.
• If contact with skin or eyes occurs, flush with water for at least 15 minutes.
• Do not ingest EBT.
• Keep EBT away from heat and flames.
• Store EBT in a cool, dark place.