# GATE (TF) Textile 2021 Question Paper Solution | GATE/2021/TF/24

###### Question 24 (Textile Technology & Fibre Science)

The wet expression for a padding mangle is set at 80 %. If the add-on of a flame retardant chemical required on the fabric is 2 % then the concentration (g/L) of the chemical in the pad bath is __25__.

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Given-Wet expression of padding mangle is 80% and add on is 2%
Formula:
Add on %=(Oven dry weight of flame retardant chemical/weight of dry fabric)*100 and
Concentration%=(Oven dry weight of flame retardant chemical/weight of flame retardant chemical paste(liquor))*100
Wet pick-up%=(weight of chemical paste/weight of dry fabric)*100
Let us assume the weight of the fabric is(dry fabric)=100 kg(kilo gram)

By applying formula:
Add on %=(Oven dry weight of flame retardant chemical/weight of dry fabric)*100
2=(dry weight of chemical/100)*100
Oven dry weight of flame retardant chemical=2kg
=2000 gm

Wet pick-up%=weight of chemical paste/weight of dry fabric*100
80=weight of chemical paste/100*100
Weight of chemical paste(liquor)=80kg Concentration(gram/litre)=2000/80 (fraction)