A mordant is used in dyeing to
- A. bleach the fabric before dyeing
- B. dissolve the dye in water
- C. remove excess dye after the process
- D. fix a dye to a fibre it would not otherwise bind to, usually by forming a metal complex
Explanation
A mordant, commonly a salt of aluminium, chromium or iron, is absorbed by the fibre first and then forms a coordination complex with the dye, anchoring it to the cloth. The metal used affects the final shade, so one dye with different mordants gives different colours. Direct dyes need no mordant because they bind to the fibre unaided.