Which chemical is used for whitening (or removal of colours) of cloth in cloth industries?

The correct answer is Calcium oxychloride.

Key Points

• Calcium oxychloride, commonly known as bleaching powder, is extensively used in the textile industry for bleaching cloth.
• Its strong oxidizing properties help in the effective removal of colors and stains from fabrics.
• Bleaching powder is preferred due to its cost-effectiveness and efficiency in large-scale applications.
• It also serves a dual purpose by disinfecting the cloth during the bleaching process.
• Calcium oxychloride is a stable compound that releases chlorine gradually, ensuring consistent bleaching action.

Additional Information

• Bleaching Powder (Calcium oxychloride):
  • Chemical Formula: Ca(OCl)₂
  • It is produced by reacting calcium hydroxide with chlorine gas.
  • It is widely used for bleaching, disinfecting water, and sanitation purposes.
  • It is a white or grayish powder with a strong chlorine smell.
• Other Chemicals Used in Textile Industry:
  • Sodium Carbonate (Na₂CO₃): Used in the dyeing process to fix dye on fibers.
  • Sodium Hydrogencarbonate (NaHCO₃): Used for neutralizing acids in textile processing.
  • Calcium Chloride (CaCl₂): Used as a desiccant and in dyeing baths to remove moisture.
• Textile Bleaching:
  • Bleaching is a chemical process that removes natural colors from fibers to achieve whiteness.
  • Common bleaching agents include chlorine-based compounds, hydrogen peroxide, and sulfur dioxide.
  • Effective bleaching ensures uniform dyeing and enhances fabric appearance.
• Safety Considerations:
  • Bleaching agents can be hazardous and should be handled with care, using proper protective equipment.
  • Proper ventilation is necessary to avoid inhalation of chlorine fumes during the bleaching process.
  • Storage of bleaching agents should be in a cool, dry place, away from direct sunlight and incompatible substances.