Alum is used by dyers of cloth:
Correct answer: B. As mordant
- A. As water purifier
- B. As mordant
- C. fire proofing fabrics
- D. Softening of hard water
Explanation
Alum acts as a mordant because it forms an insoluble complex with the dye and fibre, helping the colour adhere permanently to cloth. The likely mistake is choosing water purification, since alum is also used there to coagulate suspended impurities, but that is not its role in dyeing.
Last updated
About Dyes
Dyes are coloured organic compounds that form a stable bond or strong attraction with fibres, while pigments are generally insoluble and need a binding medium. The topic covers chromophores, auxochromes and conjugated systems, as well as acid, basic, direct, reactive, azo and mordant dyes.
Practise Industrial Chemistry
292 free Industrial Chemistry MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Chemistry questions like this
Chemistry is on 12 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.