BROMOCRESOL GREEN PAKISTAN

1. Chemical Identification

• Chemical Name: 3′,3”,5′,5”-Tetrabromo-m-cresol-sulfonephthalein

• CAS Number: 76-60-8

• Molecular Formula: C21​H14​Br4​O5​S

• Molecular Weight: 698.02 g/mol

• EC Number: 200-972-8

2. Physical & Chemical Properties

• Appearance: Fine, light-tan to reddish-brown or pale orange powder.

• Melting Point: 217–225°C (decomposes).

• Solubility: * Water: Slightly soluble (approx. 0.04% w/v).

  • Ethanol/Ether: Highly soluble.

  • Sodium Salt Form: Fully soluble in water.

• pKa: 4.7–4.9 (at 25°C).

• Stability: Stable under normal conditions; incompatible with strong oxidizing agents.

3. Indicator Range & Color Change

BCG is primarily used to track pH transitions in the acidic range.