TestUstad

Free Dyes MCQs with Answers

7 Dyes MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

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.

Last updated

7 questions

1. A dye differs from a pigment in that a dye

  • A. is always black
  • B. is insoluble and sits on the surface as fine particles
  • C. is soluble in the medium and becomes attached to the fibre
  • D. contains no colour at all

Explanation: A dye dissolves and bonds to the fibre by ionic, hydrogen or covalent bonds, so the colour becomes part of the material and resists…

Read the full explanation →
Correct answer: is soluble in the medium and becomes attached to the fibre

2. The part of a dye molecule responsible for its colour is called the

  • A. auxochrome
  • B. chromophore
  • C. monomer
  • D. catalyst

Explanation: A chromophore is an unsaturated group such as the azo linkage or a nitro group whose delocalised electrons absorb visible light, and the…

Read the full explanation →
Correct answer: chromophore

3. Azo dyes contain the group

  • A. N=N joining two aromatic rings
  • B. C=O
  • C. OH only
  • D. COOH

Explanation: The azo group links two aromatic systems into one extended conjugated network, and the resulting absorption in the visible region makes…

Read the full explanation →
Correct answer: N=N joining two aromatic rings

4. 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…

Read the full explanation →
Correct answer: fix a dye to a fibre it would not otherwise bind to, usually by forming a metal complex

5. Alum is used by dyers of cloth:

  • 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.

Read the full explanation →
Correct answer: As mordant

6. The most useful dye for those fabric which can form hydrogen bonds is:_____________?

  • A. Mordent dye
  • B. Vat dye
  • C. Acid dye
  • D. Direct dye

Explanation: Direct dyes are useful for fibres such as cellulose because their molecules can form hydrogen bonds with hydroxyl groups in the fibre.

Read the full explanation →
Correct answer: Direct dye

7. Choose group that cause solubility of the dye in acids.

  • A. -OH
  • B. -NH2
  • C. -SO2H
  • D. -COOH

Explanation: Amines are used in making azo dyes and nylon apart from medicines and drugs.

Read the full explanation →
Correct answer: -NH2
Start Free Dyes Practice MCQs Test

Dyes MCQs: common questions

Are these Dyes MCQs free?

Yes. All Dyes MCQs from Chemistry are free on TestUstad, with unlimited attempts and no account needed. Nothing on this page is a sample or a trial.

How many Dyes MCQs are on this page?

There are 7 Dyes MCQs in the Chemistry bank, shown 20 to a page with the correct answer and an explanation on each.

Does every Dyes MCQ have an explanation?

Yes. Each Dyes question shows the correct option and a written explanation of why it is correct, so a wrong answer teaches you something rather than just being marked wrong.

Can I take a timed Dyes test?

Yes. The practice button on this page starts a free Dyes test drawn from the Chemistry bank. It marks each answer instantly, gives you a score at the end, and can be retaken as many times as you like.