Tag: chemistry

Questions Related to chemistry

Dyes in litmus are made from:

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. mycorrhizae

  2. rhizoids

  3. lichens

  4. algae

Show answer
Correct Option: C
Explanation:
A water-soluble mixture which is a combination of different type of dyes which are extracted from lichens is known as litmus. This litmus is absorbed on filter paper to made one form of pH indicator, used to test the acidity or basicity of substances. 

If  greater the number the double bonds in the carotenoid dyes is more :

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. The more water soluble it is.

  2. The more non-water insoluble it is.

  3. The more intense or darker the pigment will be.

  4. The weaker the dye color will be.

Show answer
Correct Option: C
Explanation:

If more number of double bonds are present in the carotenoid system the intensity or the darkness of the pigment will increases.
Hence option C is correct.

The first dye that was prepared synthetically was:

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. Mauveine

  2. Azo-dyes

  3. Malachite green

  4. Phthalein dyes

Show answer
Correct Option: A
Explanation:

(A) Mauveine

Mauveine, also known as aniline purple and Perkin's mauve, was the first synthetic dye. It was discovered serendipitously by William Henry Perkin in 1856. It is also among the first dyes to have been mass-produced.

The chemical part of the dye that absorbs light and produces colour is called a :

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. natural pigment

  2. chromophore

  3. neon

  4. photochrome

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Correct Option: B
Explanation:
A chromophore is a group of atoms which control the colour of the dye. Thus option B is the correct answer.

A colloidal solution can be purified by following the method of:

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. dialysis

  2. peptization

  3. filtration

  4. oxidation

Show answer
Correct Option: A
Explanation:

A colloidal solution can be purified by the following methods - Dialysis, Electro-dialysis and Ultrafiltration.

Hence, option A is the correct answer.

What is the basic difference between dye and pigment?

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. Dye is an inorganic chemical that permeates fibers

  2. Dye is held to the surface of the fiber by a resin

  3. Dye diffuses into the interior of a fiber from a water solution

  4. Dyes lays on the surface of the fiber

Show answer
Correct Option: C
Explanation:

The dye is known as a coloured substance which has a great affinity towards the substrate on which it is applied. The basic difference in between dye and pigment is that dye is diffused into the interior of a given fabric from its water solution whereas pigment does not.

The dyes used in reduced state and are then oxidized in the fabric by air are called:

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. azo dye

  2. vat dye

  3. basic dye

  4. dispersed dye

Show answer
Correct Option: B
Explanation:

Vat dyes can applied directly on fibre and are generally insoluble in water. These can be used only on cotton but can not be used on silk and wool. In this case  dying is a continuous process and is carried out in a large vessel called vat. For this reason these dyes are Known as vat dyes, indigo is an example of vat dyes 

When a dye is formed on the fiber or cloth by a chemical reaction at the time of dyeing, the process is known as:

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. synthesis

  2. direct dyeing

  3. vat dyeing

  4. absorption

Show answer
Correct Option: B
Explanation:

Direct Dye is a class of dyestuff's that are applied directly to the substrate in a neutral or alkaline bath. They produce full shades on cotton and linen without mordant and can also be applied to rayon, silk, and wool. Direct dyes give bright shades but exhibit poor wash fastness. Various after treatments are used to improve the wash fastness of direct dyes, and such dyes are referred to as 'after treated direct colors". Direct dyes are molecules that adhere to the fabric molecules without help from other chemicals.

Indigo dye is an example of :

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. Azo dye

  2. Vat dye

  3. Dispersed dye

  4. Basic dye

Show answer
Correct Option: B
Explanation:

 Indigo dye is an example of Vat dye, These dyes can be used only on cotton it is a long continuous process which is carried out in a large vessel known as Vat. These dyes are applied directly on the fibre and are generally insoluble in water.

Which of the following is not a natural dye of either vegetable or animal origin?

dyes dyes and pigments chemistry in daily life applied chemistry chemistry

  1. Tyrian purple

  2. Indigo

  3. Saffron

  4. Azo dye

Show answer
Correct Option: D
Explanation:

Azo dyes are organic compounds, which contain the coloring azo function (N=M-). The azo function is often bound to an aromatic ring, and the dye can then be broken down to an aromatic amine, arylamine. This can take place either chemically, through reductive cleavage, or through the body's own enzyme system. Some azo dyes can also be broken down to arylamines during storage due to light and high temperature. Some arylamines have been judged to be carcinogenic.