Dyeing - Chemical Processing - Textile Engineering & Fibre Science Previous Year Questions

1

2007 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2007

The dye bath of solubilized vat dyes has

A

Alkaline pH

B

Neutral pH

C

Alkali and reducing agent

D

A reducing agent

Open complete paper

2

2007 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2007

Assertion: For producing denims, indigo dyeing is carried out on yarns and not on fabrics
Reason: This helps to make twill denims using undyed weft to obtain predominantly blue face and white back so that undergarments are not stained during use

A

[a] is wrong, [r] is correct

B

[a] is correct, [r] is wrong

C

[a] is wrong, [r] is wrong

D

[a] is correct, [r] is correct

Open complete paper

3

2007 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2007

A cotton fabric (110 GSM, 1 m wide) is to be dyed by pad-dry-bake sequence (wet expression 100%) on a machine running at 50 m/min. The volume of the padding liquor (V; ℓ) is kept constant by continuous replenishing
If the dye is being picked at a rate 1.2 times the rate when there is no tailing effect, the concentration (g/ℓ) of the dye bath at equilibrium would be approximately (assume that the concentration of replenishing liquor is the same as that of the initial concentration (Co; g/ℓ) of the dye bath)

A

1.25Co

B

0.83Co

C

0.62Co

D

0.54Co

Open complete paper

4

2007 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2007

If the dye bath concentration is to be kept constant at the original level Co, the concentration (g/ℓ) of the replenishing liquor would be

A

2.0Co

B

1.6Co

C

1.2Co

D

0.8Co

Open complete paper

5

2008 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2008

Choose the correct alternative for the following assertion-reason pair,
Assertion: In a wet spinning process, the counter diffusion of solvent and nonsolvent are essential in the coagulation bath for fibre formation
Reason: This ensures a constant diameter of the gel fibre

A

[a] is wrong, [r] is correct

B

[a] is correct, [r] is wrong

C

[a] is wrong, [r] is wrong

D

[a] is correct, [r] is correct

Open complete paper

6

2008 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2008

Consider the elements in Group I and Group II and choose the correct alternatives from amongst A,B,C and D

A

P-4, Q-3, R-2, S-1

B

P-4, Q-3, R-5, S-1

C

P-4, Q-1, R-6, S-2

D

P-4, Q-1, R-5, S-2

Open complete paper

7

2008 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2008

Consider the elements in Group I and Group II and choose the correct alternative from amongst A,B,C and D

A

P-6, Q-3, R-4, S-2

B

P-5, Q-2, R-4, S-1

C

P-3, Q-2, R-6, S-1

D

P-3, Q-2, R-4, S-6

Open complete paper

8

2008 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2008

A dyed fabric changed its colour to a relatively paler shade when treated with alkaline sodium sulfate solution. This suggests that

A

It was a vat dyed fabric

B

The dye got oxidized

C

The fabric was dyed from sulfur dyes

D

The dye was sensitive to alkali

Open complete paper

9

2008 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2008

In the context of dyeing of polyester with disperse dyes by exhaustion method, the relationship that holds good at any concentration of the dye in the bath [C_s], till saturation is achieved, where [C_f] and [C_s] are the dye concentrations in the solution and on the fibre respectively, is

A

[C_f] + [C_s] = constant

B

[C_f] / [C_s] = constant

C

[C_f]^-1 + [C_s]^-1 = constant

D

([C_f] + [C_s])² = constant

Open complete paper

10

2008 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2008

If the dye concentration is set to 1 g/l , the material to liquor ratio, assuming 50% exhaustion at equilibrium, would be

A

25

B

2.5

C

0.25

D

0.025

Open complete paper

11

2009 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2009

A wool/acrylic blended fabric can be dyed to solid shade using a combination of

A

Direct and acid dyes

B

Vat and acid dyes

C

Acid and basic dyes

D

Reactive and direct dyes

Open complete paper

12

2009 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2009

Consider the following elements in Group I and Group II and choose the correct alternative from amongst A, B, C and D.

A

P-5, Q-3, R-2, S-1

B

P-1, Q-2, R-5, S-4

C

P-4, Q-4, R-3, S-5

D

P-2, Q-1, R-5, S-3

Open complete paper

13

2009 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2009

The volume of the liquor in litres used on the fabric would be

A

2000

B

2400

C

2800

D

3200

Open complete paper

14

2009 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2009

The concentration (gpl) of the dye bath would be

A

40

B

35

C

30

D

25

Open complete paper

15

2010 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2010

Jet dyeing machines are built to be used with material to liquor ratio of

A

1:1

B

1:50

C

1:30

D

1:8

Open complete paper

16

2010 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2010

In the context of viscose fibre production, choose the correct statement

A

Ageing is an oxidative polymerization step

B

The coagulation bath requires acid for regeneration of cellulose

C

Ripening is carried out just before xanthation process

D

Xanthation is necessary for converting cellulose to alkali cellulose

Open complete paper

17

2010 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2010

Match the elements of Group I and Group II.\nGroup I
P. Acid dye
Q. Mordant dye
R. Reactive dye
S. Direct dye
Group II
1. Ester bonds
2. Covalent bonds
3. Electrovalent bonds
4. Co-ordinate bonds
5. Van der Waals forces
6. Ether bonds

A

P-3, Q-2, R-1, S-5

B

P-3, Q-4, R-2, S-5

C

P-5, Q-4, R-2, S-6

D

P-5, Q-2, R-1, S-6

Open complete paper

18

2010 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2010

The Nernst isotherm represents a partition of the dye between fibre and dye solution such that the value of [D]_f / [D]_s

A

Increases with increase in concentration of dye in solution

B

Decreases with increase in concentration of dye in solution

C

Does not change with increase in concentration of dye in solution

D

Increases initially with increase in dye concentration and then decreases

Open complete paper

19

2011 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2011

Match the items in Group I with those in Group II.

A

P-1, Q-2, R-3, S-4

B

P-3, Q-2, R-1, S-4

C

P-4, Q-3, R-1, S-2

D

P-4, Q-3, R-2, S-1

Open complete paper

20

2013 · Textile Engineering & Fibre Science · Chemical Processing · Dyeing

Textile Engineering & Fibre Science (TF) 2013

The highest washing fastness in a dyed cotton fabric would be obtained if the dye-fibre bond is

A

Ionic

B

Hydrogen

C

Covalent

D

Van der Waal's force

Open complete paper