Question 44 (Textile Engineering & Fibre Science)
In the case of reactive dyeing of cotton, the exhaustion is 70% and reaction efficiency is 80%. Assuming that the initial dye concentration is 2% on the weight of fabrics, the amount of unreacted dye on the fabric expressed as a percentage of fabric weight would be
| (A) | 0.14 |
| (B) | 0.28 |
| (C) | 0.35 |
| (D) | 0.42 |
Answer / Solution
Exhaustion =70%
Reaction efficiency=80%
Initial dye concentration=2%
Amount of unreacted dye on fabric expressed as a percentage of fabric=?
Calculation–
Let the fabric weight =100 kg
Weight of dye=100 x 2/100
Weight of dye=2 kg
Dye exhausted=2 x 70/100
Dye exhausted=1.4 kg
Dye reacted=1.4 x 80/100
Dye reacted=1.12 kg
Amount of unreacted dye=Exhausted dye-Reacted dye
Amount of unreacted dye=1.4-1.12
Amount of unreacted dye=0.28 kg
The amount of unreacted dye on the fabric expressed as a percentage of fabric weight=(Amount of unreacted dye/Weigh of fabric)*100
The amount of unreacted dye on the fabric expressed as a percentage of fabric weight=0.28*100/100
The amount of unreacted dye on the fabric expressed as a percentage of fabric weight=0.28 (Answer)
Hence option B is correct