74 



(a) Drop some ink on a piece of white cloth and try to 

 remove it by washing in milk. Do the same for colored 

 cloth. 



(b) Take fresh samples of the two kinds of cloth, and 

 drop ink on them as before, this time removing the stain 

 by a bleaching powder solution. 



Which method is preferable, (a) or (<)? 



(c) Rub a greasy rag over one of your colored samples, 

 and then try to remove the stain by washing the cloth in 

 hot water. If this is not effective, try soap and water. 



(d) Rub a greasy rag over one of your colored samples, 

 but this time remove the grease stain with benzine. Which 

 method of removing stains is preferable ? When could 

 one method be used and not the other ? 



(e) Put a drop of paint on a sample of cloth. Try to 

 remove it(i) with hot water, (2) with bleaching solution, 

 (3) with benzine, (4) with turpentine. 



Which is preferable ? 



(f) Drop vinegar or lemon juice on a sample of black 

 silk. What happens ? Apply weak ammonia to the spot, 

 and state the result. 



(g) Rub a rusty nail on one of your samples until an 

 iron rust stain appears. Then moisten the stain with lemon 

 juice and finally rub common salt over the discolored spot. 



If lemon juice is not available, the cloth can be dipped 

 in dilute hydrochloric acid, then rinsed in weak ammonia, 

 and finally washed in clear water. 



EXPERIMENT 68. DIRECT DYEING 



Put two grains of picric acid into 200 gm. of water and 

 mix thoroughly. Put equal amounts of the mixture into 



